African Nuclear Physics Conference 2021

20 Sep 2021, 08:00 → 24 Sep 2021, 17:00 Africa/Johannesburg

Lindsay Donaldson (iThemba Laboratory for Accelerator Based Sciences) , Rudolph Nchodu (iThemba LABS)

 

ANPC2021_Poster.pdf

Monday, 20 September

09:30 → 09:45 Welcome and Opening

Conveners: Faiҫal Azaiez (iThemba LABS) , Rudolph Nchodu (iThemba LABS)

09:45 → 11:15 Session 1: Opening Session (Mixed Topics)

Mixed Topics

Convener: Muhsin Harakeh (KVI)

09:45 R-process in neutron star mergers and magneto-rotational supernovae

The heaviest elements form by the rapid neutron capture process (r-process) in neutron star mergers and rare core-collapse supernovae. The light curve of the kilonova following the neutron star merger GW170817 showed indications of heavy elements being produced and direct observation of Strontium. This talk will report on recent breakthroughs in understanding the extreme environment in which the formation of the heavy elements occurs, as well as open questions regarding the astrophysics and nuclear physics involved.

Speaker: Almudena Arcones (TU Darmstadt and GSI)

10:15 Highlights from GANIL

In this presentation I will show some recent results obtained at GANIL.

Speaker: Olivier Sorlin (GANIL)

10:45 Heavy Ions in Therapy and Space

Research in the field of biological effects of heavy charged particles is needed for both heavy-ion therapy (hadrontherapy) and protection from the exposure to galactic cosmic radiation in long-term manned space missions. Although the exposure conditions (e.g. high- vs. low-dose rate) are different in therapy and space, it is clear that a substantial overlap exists in several research topics, such as individual radiosensitivity, mixed radiation fields, and tissue degenerative effects. Late effects of heavy ions are arguably the main health risk for human space exploration, and with the increasing number of cancer patients treated by heavy-ion therapy, including young adults and children, this issue is now becoming the main source of uncertainty for the success of hadrontherapy as well. Reducing uncertainty in both cancer and noncancer late risk estimates is therefore the first priority in heavy-ion radiobiology. In addition, researchers involved either in experimental studies on space radiation protection or heavy-ion therapy often use the same accelerator facilities. Several heavy-ion therapy facilities are now under construction or planned in Europe, USA, and Japan. Beamtime will be available at these facilities for clinical radiobiology and basic heavy-ion effects experimental research, as already happens since several years at the HIMAC in Japan. The NASA Space Radiation Laboratory (NSRL) in Brookhaven (Long Island, NY) provides beams of very heavy ions at energies around 1 GeV/n which are of specific interest for space radiobiology. In Europe, these very high energy beams are available at GSI in Germany, where the new Facility for Antiprotons and Ion Research (FAIR) is currently under construction. It is foreseeable that the availability of beamtime and the presence of many dedicated research programs will lead to great improvements in our knowledge of biological effects of heavy ions in the coming few years.

Speaker: Marco Durante (GSI)

11:15 → 11:30 Tea/Coffee/Short Break

11:30 → 13:30 Session 2: Nuclear Structure, Reactions and Dynamics

Convener: Nasser Kalantar-Nayestanaki (KVI-CART)

11:30 Complementarity and Future Prospects on experiments using the high-resolution magnetic spectrometers at RCNP and iThemba LABS

Studies of nuclear excited states using High-resolution light-ion reactions have extensively been performed at RCNP and iThemba LABS in the past decades. Both facilities are unique for realizing zero-degree inelastic scattering experiments using proton or alpha particles and for the high-resolution capability of 20 keV.
For example, the proton-scattering experiment at zero degrees [1] has enabled the studies of electric dipole (E1) strengths of the giant and pygmy dipole resonances by Coulomb excitation, gamma-strength function, and spin-M1 excitations by nuclear excitation. Fluctuation analysis of high-resolution spectra has provided information on the level density above the neutron threshold. Isoscalar excitation strength distribution, e.g., giant monopole resonance, has been measured by inelastic alpha scattering [2].
We have recently started a joint project, PANDORA (Photo-Absorption of Nuclei and Decay Observation for Reactions in Astrophysics) [3], among RCNP, iThemba LABS, and ELI-NP, aiming to study photo-nuclear reactions below a mass of A=60. The primary motivation of the project is to measure reliable systematic data on the photo-absorption cross-sections and p-, alpha-, n- and gamma-decay branching ratios by combining Coulomb excitation and real-gamma beam experiments. Both the RCNP and iThemba LABS employ the Coulomb excitation by proton scattering. The former facility can measure excited states up to the higher energy of 32 MeV, but the latter is advanced for the efficient charged-particle and gamma detectors.
At the conference, I plan to introduce the unique features and the highlights of the RCNP and iThemba LABS facilities, including the advantages of each facility and the complementary future projects.

[1] P. vonNeumann-Cosel and A. Tamii, Eur. Phys. J. A 55, 110 (2019).

[2] U. Garg and G. Colò, Prog. in Part. and Nucl. Phys. 101, 55 (2018).

Speaker: Atsushi Tamii (Research Center for Nuclear Physics, Osaka University)

12:00 Electric and magnetic dipole response in $^{58}$Ni from inelastic proton scattering

Inelastic proton scattering at very forward angles is an excellent tool for studying the dipole response in nuclei [1]. Reactions with intermediate proton energies of a few hundred MeV and scattering angles close to 0$^\circ$ are particularly suited to investigate the isovector spin-flip M1 resonance due to the strong spin-isospin dependent part of the effective proton-neutron interaction in this kinematics. Furthermore, the electric dipole response can be measured over a wide excitation energy range. This provides information about the electric dipole polarizability which is related to the neutron-skin thickness and the density dependence of the symmetry energy parameter [2,3].
An inelastic proton scattering experiment with a 295 MeV proton beam on a $^{58}$Ni target was performed at the Reserach Centre for Nuclear Physics (RCNP) in Osaka. A high energy resolution of $\approx$ 20 keV FWHM could be achieved. Electric and magnetic dipole contributions to the cross section were obtained by a multipole decomposition analysis based on DWBA calculations. The dipole strength distribution of $^{58}$Ni has been extensively measured with nuclear resonance fluorescence [4,5] and inelastic electron scattering [6]. A comparison of the different methods sheds light on various features of nuclear structure such as spin and orbital contributions to the magnetic dipole strength and the nature of low-energy electric dipole transitions.
$ $
[1] P. von Neumann-Cosel and A. Tamii, Eur. Phys. J. A 55, 110 (2019).
[2] A. Tamii et al., Phys. Rev. Lett. 107, 062502 (2011).
[3] J. Birkhan et al., Phys. Rev. Lett. 118, 252501 (2017).
[4] M. Scheck et al., Phys. Rev. C 88, 044304 (2013).
[5] J. Sinclair, priv. com. (2019).
[6] W. Mettner et al., Nucl. Phys. A473, 160 (1987).
Supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - Project-ID 279384907 - SFB 1245.

Speaker: Isabelle Brandherm (TU Darmstadt)

12:20 Transfer reactions to populate the PDR in 96Mo

The pygmy dipole resonance (PDR) is a cluster of 1- states around and below the neutron separation energy and has gained traction in nuclear structure studies. The microscopic nature of the PDR is still an open question in particular, whether these 1- states could be defined as collective or being dominated by specific single-particle configurations. The study here presented is one of the first attempts to investigate the question of collectivity by exploiting the sensitivity of one-particle transfer reactions to excite single-particle states. The measurements of transfer reactions (p,d) and (d,p) were performed on two different targets to populate the $^{96}$Mo residual nucleus. The ejectiles were detected, identified and momentum-analyzed by the MAGNEX spectrometer and its focal-plane detector which is installed at the Laboratori Nazionali del Sud of Instituto di Fisica Nucleare (INFN-LNS) in Catania, Italy. In this talk, the data reduction process of the (p,d) reaction will be presented together with some preliminary results.
This work is based on the research supported in part by the National Research Foundation (NRF) of South Africa grant number 118846.

Speaker: Thuthukile Khumalo (iThemba LABS)

12:40 Low-lying dipole and quadrupole states as new excitation modes

We briefly review the properties of the low-lying dipole states known as Pygmy Dipole Resonance trying to select the main one which could define this new excitation mode. A good candidate seems to be the isoscalar-isovector mixing which has been proved by both theoretical and experimental investigations. On the other hand, the study of the low-lying quadrupole states do not seem to provide clear evidence for a new excitation mode. The theoretical approaches used to investigate the quadrupole response reach different conclusions and the experimental data can only clearly establish the multipolarities of the states and their one-phonon character. Moreover, cross section calculations are not sensitive enough to disentangle between quadrupole states which are considered, in one of the theoretical approach, as due to different excitation mode.

Speaker: Edoardo G. Lanza

13:00 In-beam gamma-ray spectroscopy at RIKEN

At the Radioactive Isotope Beam Factory at the RIKEN Nishina Center in-beam gamma-ray spectroscopy experiments take advantage of the wide range of radioactive ion beams produced by the projectile fragmentation and fission. Isotopes of interest are separated by the BigRIPS fragment separator and guide to a secondary target. Reaction residues are identified either in the ZeroDegree spectrometer or with the SAMURAI setup. Gamma rays emitted at the reaction target are detected with high efficiency in the DALI2 NaI(Tl) array. The HiCARI project (High-resolution Cluster Array at RIBF) aimed at overcoming the limitations of the DALI2 array by combining several germanium based detectors from around the world. In 2020/21, an experimental campaign was launched studying neutron-rich nuclei from Ca to Te isotopes with high resolution using HiCARI.
The physics program includes a wide range of topics in nuclear structure addressing collective and single-particle structure of nuclei very far from stability. In this talk, I will present selected results on the spectroscopy of very exotic nuclei and discuss future prospects of in-beam gamma-ray spectroscopy at the RIBF.

Speaker: Kathrin Wimmer

13:30 → 14:00 Meal/Long Break

14:00 → 15:30 Session 3: Mixed Topics

Convener: Sotirios Charisopoulos (IAEA)

14:00 Precision electroweak measurements of the neutron radii of calcium and lead

The RMS radius of neutrons within a nucleus may be measured cleanly, and without model dependence arising from hadronic interactions, through the parity-violating electroweak asymmetry in the elastic scattering of longitudinally polarized electrons. The PREX2 and CREX experiments recently measured the neutron radius of lead-208 and calcium-48 with varied physical implications from the understanding of neutron stars to the role of 3-neutron forces in microscopic models, and together provide a meaningful constraint on the density dependence of the symmetry energy in neutron rich nuclear matter, a parameter of the nuclear equation of state. The analysis and results of the experiment will be presented, along with a brief discussion of the experimental techniques and challenges required to achieve this precise measurement.

Speaker: Mark Dalton (Jefferson Lab)

MarkDalton_PREX2_ANPC21.pdf

14:30 Upgrade of the iThemba LABS Fast Neutron Beam Facility towards ISO/IEC 17025 Accreditation

The iThemba LABS fast neutron beam facility (D-line vault) is an international niche facility that can provide ns-pulsed quasi-monoenergetic neutron beams in the energy range of 30 to 200 MeV. Other available neutron beam facilities, with energy range similar to this facility, are described in details by the EURADOS (European Radiation Dosimetry) Report [1]. In the D-line, quasi-monoenergetic neutron beams are typically produced via $^7$Li(p,xn) or $^9$Be(p,xn) reactions using proton beams available from the separated sector cyclotron (SSC). The facility first became operational in the late 1980s [2] and had remained practically unchanged for over 30 years. The Themba LABS fast neutron beam facility has been designated by the National Metrology Institute of South Africa (NMISA) to be an entity responsible for providing traceability for the medium and high-energy neutron measurements in South Africa. As a result, the facility has to undergo a major upgrade and development in order to achieve ISO/IEC 17025 accreditation status for the medium and high-energy neutron region. We present the status on the progress of the D-line vault upgrade, including preliminary results from previous measurements of the neutron background from the original configuration of the vault.

Speaker: Zina Ndabeni (University of Cape Town / iThemba LABS)

14:50 Flow measurement and characterisation from positron annihilation

Flow following tracer particles containing short lived positron emitting species are placed inside physical and engineering devices. The pairs of photons produced by positron annihilation are detected in coincidence by large arrays of high speed position sensitive detectors, and used to determine the near-instantaneous position of the tracer. Hence the resulting bulk dynamics occurring inside the device are inferred in a technique known as Positron Emission Particle Tracking (PEPT).

At the largest multidisciplinary national research facility in South Africa, the iThemba Laboratory for Accelerator Based Sciences (iThemba LABS), PEPT is used by the University of Cape Town group to study dynamic physical processes, turbulent, and multiphase flow phenomena. Such studies are of interest to industry, particularly in the South African context of mining and minerals processing. Further applications address global challenge topics including problems of water scarce environments, reducing industrial wastes, and towards sustainable economies through improved process efficiencies and design led approaches.

The applications of PEPT, and alternative complimentary measurement techniques, have enabled the development of flow metrology systems applicable to real world problems. Recent research produced by the PEPT Cape Town laboratory will be discussed, including aspects of our four key themes: instrumentation & detector development, radioisotope tracer techniques (physical and chemical), data acquisition & processing, and applications.

Speaker: Thomas Leadbeater (University of Cape Town)

204-TW_Leadbeater-FlowMeasurementAndCharacterisationFromPositronAnnihilation.mp4

15:30 → 15:45 All Delegates Move Over to Poster Session - Gather.Town

15:45 → 17:45 Poster Session 1: Mixed Topics

Sponsored by School of Physics, University of the Witwatersrand

15:45 A compact neutron spectrometer for neutrons produced by cosmic rays

Cosmic rays are comprised largely of high energy protons and alpha particles which create large amounts of secondary particles through spallation when they interact with our atmosphere. At aviation altitudes the radiation field is made up predominantly of neutrons in the energy range 1 - 100 MeV [1]. During space weather events, such as solar flares, the number of energetic particles entering the atmosphere can increase drastically resulting in higher radiation doses to aircrew, and an increased risk of electronics malfunction on board aircraft [2]. As these events are unpredictable and short-lived, very little observational data exist.

The development and characterisation of a compact detector to measure cosmic ray induced neutrons with energies up to 100 MeV on board aircraft is presented. Building upon previous research at UCT [3,4,5], the prototype detector comprised of a 6 mm x 6 mm x 50 mm slab of EJ-276 plastic scintillator, a SensL C-series silicon photomultiplier, and digital data acquisition. Results from the first measurement campaign at n-lab (UCT) utilising mixed gamma ray and neutron fields with energies up to 4.4 MeV and 14.1 MeV respectively are presented. Overall, the detector system performed well and showed promise of being suitable for the measurement of neutrons with energies up to 100 MeV. Further development of the device is ongoing in collaboration with SANSA and iThemba LABS, and a design which optimises neutron detection and light collection has been identified using Geant4 simulations. Future work aims characterise the response of the detector up to 100 MeV and perform measurements in an in-flight scenario.

[1] P. Goldhagen, et al., Rad. Prot. Dos., vol.110, p.387 (2004)
[2] W. Tobiska, et al., Space Weather, 13, 202–210 (2015).
[3] A. Buffler, et al., Int. Jour. Mod. Phys. 44, 1660228 (2016).
[4] A. Comrie, et al., Nucl. Instr. Meth. A, 772, 43–49 (2015).
[5] E. Jarvie, A new pocket-sized neutron detector, Hons. Thesis, Dept. Physics, UCT, 2020

Speaker: Erin Jarvie (University of Cape Town)

205-EA_Jarvie- A_compact_spectrometer_for neutrons_produced_by_cosmic_rays.pdf

15:45 A new fast neutron facility for materials analysis at UCT

Neutron-based nuclear techniques such as fast neutron analysis (FNA) and thermal neutron analysis (TNA) are among the most powerful techniques for elemental analysis in small and bulk samples [1, 2]. The techniques are rapid, non-destructive, and are capable of multi-elemental analysis of samples with complex matrices. Neutron-based techniques are often used in the minerals industry, where fast neutrons are used for on-line analysis of coal, and the safety and security industry, where neutrons can be used for detection of contraband and explosives in cargo containers and in vehicles [3, 4]. Analysis of materials using neutron-based techniques involves irradiating a sample with a field of neutrons with a known energy distribution and neutron flux. The interaction of incident neutrons with the sample nuclei leads to an emission of several signatures – mainly gamma-rays, scattered neutrons and transmitted neutrons, which are characteristic to the elemental composition of the sample [3, 5].

In 2017, the Metrological and Applied Sciences University Research Unit (MeASURe) within the UCT Department of Physics commissioned the n-lab, a fast neutron laboratory [6] centred around a Thermo MP-320 deuterium-tritium sealed tube neutron generator (STNG) and a 220 GBq Americium-Beryllium (Am-Be) radioisotopic source. The aims of this project are to characterise the n-lab as a facility for FNA and TNA, and to develop standardised analysis protocols for the elemental analysis of bulk materials. Fundamental to FNA and TNA is the knowledge of the number and energy distribution of neutrons incident upon the sample of interest. The fast neutron yield of the STNG has been measured to be (1.23 ± 0.29)E+08 s-1 using the foil activation method, and is in agreement with the expected value for this particular device.

References

[1] J. Csikai, Proc. SPIE 2339, 318-334 (1995)
[2] Z. Alfassi, Activation Analysis Vol.1, CRC Press (1990).
[3] Sowerby, B.D., 2009, Applied Radiation and Isotopes 67, 1638-1643.
[4] Brown, D.R., et al., 1994, Nuclear Instruments and Methods in Physics Research A 353, 684-688.
[5] Brooks, F.D., et al., 1998, Nuclear Instruments and Methods in Physics Research A 410, 319-328.
[6] T. Hutton & A. Buffler, Proceedings of SAIP2017, SA Institute of Physics (2018).

Speaker: Mr Sizwe Mhlongo (University of Cape Town)

176-SS_Mhlongo-A new fast neutron facility for materials analysis at UCT.pdf.pdf

Mhlongo-ANPC_abstract.pdf

15:45 A study on the photon interaction parameters of some meteorite samples

The goal of this work is to research photon interaction parameters of four meteorite samples which have various elemental contents from the scientific literature. Mass attenuation coefficients, effective atomic number values, effective electron density values, coherent scattering cross sections, incoherent scattering cross sections, photoelectric absorption cross sections, pair production cross sections for atomic nucleus and pair production cross sections for atomic electrons of present meteorite samples were obtained theoretically using computer software in energy range from 1 keV to 100 GeV. Consequently, photon interaction parameters of four meteorite samples vary depending on the incident photon energy and elemental components of the meteorite samples.

Speaker: Dr Canel Eke (Akdeniz University)

131-Canel_Eke-A_study_on_ the_photon_interaction_parameters_of_some_meteorite_samples.pdf

15:45 Cluster excitation and alpha radioactivity within covariant EDF framework

The use of Energy Density Functional (EDF) method within a relativistic framework showed, this last decades, that it can both describe the bulk properties of nuclei (radii, GS energy, binding energy, ...)[1] as well as clusters formation[2].
The study of cluster structures allow for many applications ranging from $\alpha$ or cluster decay to many different kinds of excitations.
This last few years, new techniques such as the Finite Amplitude Method (FAM) [3,4,5] open new possibilities in the computation of collective response of nuclei: a fully microscopical calculation for axially deformed nuclei is made possible within this framework. Such deformed calculations are necessary to describe clusters behaviors.

Many experimental results show significant transition strengths in light nuclei at low energy below giant resonance transition. In some cases, these low energy excitations can be associated with $\alpha$ cluster states. The use of FAM provides an efficient tool, less demanding on the numerical side than the usual QRPA method. The ground state calculations are performed over several isotopic chains using relativistic energy density functional method.
This approach allows for a fully microscopic treatment from the nucleonic degree of freedom, and does not require any ansatz on the nature of the single particle wave-function nor the ground state itself. The same universal pattern at low energy is found in the case of Ne, Mg and other isotopes, for the different multipoles[6]. The associated transition densities show a cluster structure linked with $\alpha$ or cluster oscillations.

A more extreme phenomenon to be studied within the covariant EDF framework is the one of radioactivity where cluster are pre-formed and emitted. Previous studies showed that a reliable description of cluster radioactivity in heavy nuclei was achievable[7].
The description of $\alpha$ radioactivity has recently been carried through within RMF framework at both qualitative and quantitative levels[8]. A new 2$\alpha$ decay mode is even predicted for some heavy nuclei with lifetime close to cluster emission[9].

[1] G. A. Lalazissis, T. Nikšić, D. Vretenar, and P. Ring, Phys. Rev. C 71, 024312 (2005).
[2] J.-P. Ebran, E. Khan, T. Nikšić and D.Vretenar, Nature 487, 341 (2012).
[3] T. Nakatsukasa, T. Inakura, K. Yabana, Phys. Rev. C76, 024318 (2007).
[4] P. Avogadro, T. Nakatsukasa, Phys. Rev. C84, 014314, (2011).
[5]T. Nikšić, N. Kralj, T. Tutiš, D. Vretenar, and P. Ring, Phys. Rev. C88, 044327 (2013).
[6] F. Mercier, A. Bjelčić, T. Nikšić, J.-P. Ebran, E. Khan, and D. Vretenar, Phys. Rev. C 103, 024303 (2021).
[7] M. Warda and L. M. Robledo, Phys. Rev. C 84, 044608 (2011).
[8] F. Mercier, J. Zhao, R.-D Lasseri, J.-P. Ebran, E. Khan, T. Nikšić, and D. Vretenar, Phys. Rev. C 102, 011301(R) (2020).
[9] F. Mercier, J. Zhao, J.-P. Ebran, E. Khan, T. Nikšić, and D. Vretenar, Phys. Rev. Letter (to be published).

Speaker: Florian Mercier (IJCLab, Orsay, France)

149-F_Mercier_Low_energy_excitations_Poster.pdf

Abstract_ANPC_Mercier.pdf

15:45 Competing excitation modes in A $\sim$ 80 region

The level structure of neutron rich nucleus, $^{78}$As has been investigated at the low- and medium-spin regime through the alpha-induced fusion evaporation reaction, at varying beam energies, using the mylar backed enriched $^{76}$Ge target. The de-excited gamma rays were detected using the INGA (Indian National Gamma Array) spectrometer stationed at VECC, Kolkata, India. The level scheme of $^{78}$As has been constructed using the standard gamma-ray spectroscopic techniques. The use of both Clover and LEPS detectors provided additional
scope for proper identification and unambiguous placements of the low-energy gamma transitions (having $E_{\gamma}$ $\leq$ 80 keV) in the level scheme. The observed low-lying, low-spin level structure is found to be highly irregular suggesting the dominance of single-particle excitation modes. The onsets of regular positive- and negative-parity dipole band-like structures are found to be developed at the medium-spin excitation regime. Based on the detail theoretical calculations (shell model calculations, TRS calculations, and the semi-empirical calculations for shears mechanism) and the level structure systematics, these band-like structures are interpreted to originate from the novel excitation mode known as "stapler"-like shears mechanism. It is interesting to note that while both the intruder orbitals, $\pi(1g_{9/2})$ and $\nu(1g_{9/2})$ are found to have dominnat contributions in generating the positive-parity states, the intruder $\pi(1g_{9/2})$ orbital does not seem to have any role in generating the negative-parity states. The details about the level structure of $^{78}$As obtained from the present investigation will be presented at the conference.

This is a part of the work carried out using the financial assistance from the DAE-BRNS, Government of India [Project Sanction No. 37(3)/14/17/2016-BRNS]. The financial support and co-operation received from UGC-DAE CSR, Kolkata, India through Project No.: UGC-DAE-CSR-KC/CRS/19/NP10/0921/0963 is gratefully acknlowledged. The help and support received from all the collaborators at different stages of the work is deeply acknowledged.

Speaker: Dr Anagha Chakraborty (Department of Physics, Siksha Bhavana, Visva-Bharati University)

137-A_Chakraborty-Competing_excitation_modes_in_A~80_region.pdf

15:45 Davydov-Chaban Hamiltonian within the formalism of deformation-dependent effective mass for Kratzer potential

In this work, we modify the Davydov-Chaban Hamiltonian describing the collective motion of a $\gamma$-rigid atomic nucleus by allowing the mass to depend on nuclear deformation. Exact analytical expressions are derived for energy spectra as well as normalized wave functions for Kratzer potential. The model called Z(4)-DDMD (Deformation Dependent Mass with Kratzer potential), is achieved by using the Asymptotic Iteration Method (AIM). The numerical calculations for energy spectra and B(E2)transition probabilities are compared to the experimental data of $^{192−196}$Pt isotopes. The obtained results show an overall agreement with the experiment and an important improvement in respect to other models

Speaker: Prof. Alaaeddine Lahbas (ESMaR, Department of Physics, Faculty of Sciences, Mohammed V University in Rabat, Morocco)

107-A_LAHBAS-Davydov_Chaban_Hamiltonian_within_the_formalism_of_deformation_dependent_mass_for_Kratzer_potential.jpg

107-A_LAHBAS-Davydov_Chaban_Hamiltonian_within_the_formalism_of_deformation_dependent_mass_for_Kratzer_potential.pdf

Preview-107-A_LAHBAS-Davydov_Chaban_Hamiltonian_within_the_formalism_of_deformation_dependent_mass_for_Kratzer_potential copie.jpg

15:45 Density modified tracer particles for Positron Emission Particle Tracking (PEPT)

PEPT Cape Town has pioneered the development of Gallium-68 based tracer particle analogues for use in positron emission particle tracking studies of granular and multiphase systems. The accuracy of the measured data relies strongly on how representative the tracer particle analogue is to the media of interest in these dynamic systems. The ability to control and manipulate the tracer fabrication methods expands the range of applications and systems suitable for investigation with PEPT. The density of the material under investigation is often a critical parameter of the system under study. Tracer production methods developed at PEPT Cape Town rely on multiple layer coatings of tracers created by radiolabelling ion exchange resin beads. The layers include the radioactive core, a density controlled region and may include an additional coating used to control the surface chemistry of the particle. The current available densities range between 1.00 and 2.85 g cm-3 with particle diameters as small as 450 microns. We report on the current state of density-modified tracer particles and illustrate the method using data from PEPT measurements on an industrial system designed to separate higher density minerals from lower density gangue.

Speaker: Mr Michael van Heerden (University of Cape Town)

213-MR_van Heerden_Characterising_fluid_flow_using_Positron_Emission_Particle_Tracking.pdf

15:45 DICER: A new device for indirect capture experiments on radionuclides

Direct neutron capture measurements on short-lived radionuclides can be extremely challenging, if not impossible using current techniques. Therefore, indirect methods have been developed. A new apparatus was installed at the Los Alamos Neutron Science Center (LANSCE) to measure neutron total cross sections on small radioactive samples as an indirect means to tightly constrain their neutron-capture cross sections. The first year of operation indicates that the instrument is ready to perform its first measurement on a radioactive sample (88Zr, t1/2=83.4 days). The experiment is planned for the summer of 2021 in collaboration with the Isotope Production Facility (IPF), also at LANSCE. A description of the apparatus and details of the experiment will be presented.

Speaker: Dr Athanasios Stamatopoulos (Los Alamos National Laboratory)

146_AStamatopoulos_DICER.pdf

abstract_ANPC_2021.pdf

15:45 Dipole excitations in $^{162}$Er - $^{166}$Yb

Particle-hole symmetry reveal some degenerate experimental observable for nuclei having equal N$_{p}$N$_{n}$. Up to date, E(2$^+$), E$_{4^+}$/E$_{2^+}$, B(E2; $2^+ \rightarrow 0^+$), spectroscopic factors for alpha decay, binding energy and moment of inertia have been investigated as a function of N$_{p}$N$_{n}$[1]. Recently, it has been shown that nuclei having particle-hole symmetry reveal similar excitation patterns up to 10$^+$ in yrast bands. $^{162}$Er and $^{166}$Yb nuclei having particle hole symmetry show similar excitation patterns in the yrast, $\gamma$ and $\beta$ bands. In the present work, we are aiming to investigate the dipole excitation modes in $^{162}$Er and $^{166}$Yb. These features have not been investigated within this perspective so far. We investigate the dipole structure properties of the deformed of these nuclei in the dipole resonance energy region within the framework of the quasiparticle random-phase approximation (QRPA), which is one of the models taking account the quasiparticle and pairing interactions[2-6]. Due to the mean field features of the QRPA, spontaneous broken of the translational and Galilean symmetries of the single particle Hamiltonian are observed. In this context, we also aim to investigate the effects of both translation and Galilean (TGI) restorations invariance QRPA on the dipole properties of $^{162}$Er and $^{166}$Yb whether they reveal a similar behaviour or not as in the low-lying excitation modes.

1- R.F. Casten, Nucl. Phys. A443, (1985) 1.
2- Ring P. and Shuck P.,The Nuclear Many Body Problem(Springer Verlag New York,2001).
3- T. Oishi, M. Kortelainen and N. Hinohara,Phys. Rev. C93(Mar 2016) 034329.
4- K. Yoshida and T. Nakatsukasa,Phys. Rev. C83(Feb 2011) 021304.
5- K. Yoshida and T. Nakatsukasa,Phys. Rev. C88(Sep 2013) 034309.
6- V. O. Nesterenko, V. G. Kartavenko, W. Kleinig, J. Kvasil, A. Repko, R. V. Jolosand P.-G. Reinhard,Phys. Rev. C93(Mar 2016) 034301

Speaker: Nilufer Demirci Saygı

116_N.Demirci-Saygı_Dipole excitations in 162Er - 166Yb poster.pdf

15:45 Disappearance of channel coupling effects in $^{12}$C + $^{24}$Mg fusion far below the barrier

Evidence for fusion hindrance in $^{12}$C + $^{24}$Mg was suggested by a recent experiment where the excitation function was over-estimated by standard CC calculations, and a pronounced indication of an S factor maximum vs energy was observed [1].
This system is slightly heavier than those of astrophysical interest, like $^{12}$C + $^{12}$C and $^{16}$O + $^{16}$O. Further measurements on $^{12}$C + $^{24}$Mg have been performed in the present work, with the purpose of extending the excitation function to lower energies and adding intermediate energy points to better characterise its overall behaviour.
The present experiment has been performed using high-quality $^{24}$Mg beams from the XTU Tandem accelerator of INFN - Laboratori Nazionali di Legnaro by directly detecting the fusion evaporation residues (ER) at very forward angles. We have
extended the excitation function down to around 4 μb, and the new data points confirm the presence of hindrance in $^{12}$C + $^{24}$Mg undoubtedly. The cross-section at the hindrance threshold is indeed found to be remarkably large, in agreement with the result of the previous measurement. The S-factor develops a clear maximum vs energy, that is nicely fitted using both an empirical interpolation in the spirit of the adiabatic model [2], and the hindrance parametrisation.
Coupled-channels calculations have been performed using the same Woods-Saxon potential of the previous paper. The new data far below the barrier may suggest that the coupling strengths gradually decrease and vanish so that the excitation
function seems to be well reproduced by simple one-dimensional tunnelling through the potential barrier in that energy range. On the other hand, the equally good fit obtained with the hindrance model [3] indicates that discriminating between the two
approaches would require further precise cross-section measurements at lower energies.

(please see figure in the attached pdf file)

FIG. 1: (left) Fusion excitation function of $^{12}$C + $^{24}$Mg measured in [1] (blue dots), and the new present data (red dots), compared to CC calculations (see text). (right) Astrophysical S-factor derived from the two data sets, compared to CC calculations and fitted according to the adiabatic and hindrance model [2, 3].

[1] G. Montagnoli et al., Phys. Rev. C 101 (2020) 044608
[2] T. Ichikawa, K. Hagino, and A. Iwamoto, Phys. Rev. C 75 (2007) 057603
[3] C.L.Jiang, K.E.Rehm, B.B.Back and R.V.F.Janssens, Phys. Rev. C 79 (2009) 044601

Speaker: Mirco Del Fabbro (Dip. di Fisica e Scienze della Terra Univ. di Ferrara and INFN Padova )

12C+24Mg_fusion_DelFabbro.pdf

134-M_DelFabbro-12C+24Mg_fusion.pdf

15:45 Experimental investigation of nuclei in A ~ 50 - 60 region

The proton and neutron Fermi levels in nuclei with mass number A ~ 50 - 60 lie around the N = Z = 28 magic number. This shell gap is comparatively smaller which might have made the doubly magic $^{56}$Ni (N = Z = 28) a soft core [1]. The 1g$_{9/2}$ orbital, lies above fp orbital, has shape driving effect which leads to deformation and collectivity. Therefore, in these nuclei there is a competition between the single particle and collective excitations. Different nuclear shapes and shape transitions are expected for these nuclei, some of which have been observed [1-3].

We have performed an experiment at VECC, Kolkata using $^{55}$Mn($^4$He,2p3n) reaction with 34-MeV $\alpha$ beam from the K-130 cyclotron to populate the nuclei near the vicinity of $^{56}$Ni. The primary aim was to study the odd-odd nucleus $^{54}$Mn (Z = 25, N = 29), which has 3h-1p ground state configuration with respect to $^{56}$Ni. Being an odd-odd nucleus, different coupling possibilities exist between different valence proton and neutron orbitals which would lead to the production of several low-lying yrast and non yrast states. The experimental evidence of these states would provide information on the proton-neutron interaction.

The de-excited prompt gamma rays, emitted from the populated nuclei, were detected using a multi detector gamma-ray spectrometer consisting of 11 Compton-suppressed clover HPGe detectors and 1 LEPS detector. The clover detectors were at three angles, 40$^\circ$ (2 clovers + LEPS), 90$^\circ$ (6 clovers) and 125$^\circ$ (3 clovers). The PIXIE-16 digitizer based data acquisition system and IUCPIX package, developed by UGC-DAE CSR Kolkata [4], was used to record and process the data. While the detailed analysis of the data is in progress, the preliminary analysis of the coincidence matrix constructed from the addback energies from the clover detectors clearly indicates the production of excited states in other odd-even ($^{57}$Co, $^{55}$Mn) and even-odd ($^{57}$Fe) nuclei in addition to $^{54}$Mn. Another experiment ($\alpha$ + $^{58}$Ni) was also performed at VECC using similar detector setup to study the higher Z nuclei in this region [5].

According to the present data analysis, some states of $^{54}$Mn reported in [6] are found to be highly questionable. The parity of a low lying state at ~1.9 MeV has been assigned as negative by [6]. The negative parity at such a low excitation is highly interesting for this nucleus. This is also under inspection. A few new gammas have also been identified in the present work. In addition, evidence of rotational band has been found in the odd-A isotope $^{55}$Mn. Further data analysis is in progress.

References:
[1] E.K. Johansan et.al. , Eur. Phys. J. A27, 157-165 (2006)
[2] C.–H Yu et al., Physical Review C65, 061302(R) (2002)
[3] N. Bendjaballah et al. Phys. Rev. Lett 36, 1536 (1976)
[4] S. Das et al., Nucl. Inst. Meth. Phys. Res. A 893, 138 (2018)
[5] S. Basu et al., VECC Ann. Prog. Rep. 2019-20 P35
[6] G. Kiran Kumar et al. J. Phys. G: Nucl. Part. Phys. 35, 095104(2008)

Speaker: Mr Sansaptak Basu (Variable Energy Cyclotron Centre, Kolkata-700064, India ; HBNI, Training School Complex, Anushaktinagar, Mumbai-400094, India)

151-S_Basu- Experimental_ investigation _of_ nuclei_ in_ A ~ 50 - 60_ region.pdf

ANPC_Sansaptak.pdf

15:45 First observation of a rotational band in neutron-deficient $^{187}$Pb: evidence for triple shape coexistence

A prompt and delayed $\gamma$-ray spectroscopy of neutron-deficient isotope $^{187}$Pb has been performed using the recoil-decay tagging and the isomer-decay tagging techniques at Argonne Gas-Filled Analyzer (AGFA). A new 4.66(4) $\mu$s isomer and a strongly-coupled band on top of it were identified. The band looks nearly identical to a band built on top of the 7/2$^{-}$[514] Nilsson orbital in the isotone $^{185}$Hg. Based on this similarity and on the potential-energy surface (PES) and particle-plus-rotor (PPR) calculations, the new isomer in $^{187}$Pb is also proposed as originating from the same configuration. Combining this result with the previous studies, evidence for triple shape coexistence at low energy has been found in both negative and positive parity configurations in $^{187}$Pb. Furthermore, the almost identical properties between the 7/2$^{-}$[514] bands in $^{187}$Pb and $^{183,185}$Hg were discussed.

Speaker: Wenqiang Zhang (Institute of Modern Physics, Chinese Academy of Sciences)

148-Wenqiang_Zhang-First observation of low-lying strongly-coupled prolate band in neutron-deficient semi-magic 187Pb.pdf

15:45 In-beam spectroscopy of 94Ag

The formal concept of isospin has been introduced to explain the apparent exchange symmetry between neutrons and protons. However, if the nuclear force were the same for protons and neutrons properties such as masses and excitation energies would depend only on the mass number A. Recent studies have shown that the Coulomb force cannot account for all deviations, suggesting that other isospin-symmetry-breaking components must be present. N⁓Z systems present the perfect testing ground to probe isospin symmetry phenomena [1-3]. In particular, pairing correlations have a significant importance in the description of the nuclear structure of N=Z nuclei, where protons and neutrons are arranged occupying the same orbits, allowing T=0 np pairing in addition to the normal T=1. It was recently suggested that spin-aligned T=0 np pairs dominate the wavefunction of the y-rast sequence in $^{92}$Pd [4]. Subsequent theoretical studies were devoted to probe the contribution of np pairs in other N=Z A>90 nuclei [5-6], suggesting that a similar pairing scheme strongly influences the structure of these nuclei. In an effort to answer this question further, a recoil beta tagging experiment has been performed to try and identify the excited T=0 and T=1 states in odd-odd N=Z $^{94}$Ag using the $^{40}$Ca($^{58}$Ni,p3n)$^{94}$Ag reaction. The experiment was conducted using MARA recoil separator and JUROGAM3 array at the Accelerator Laboratory of the University of Jyväskylä.

The detailed goals of the experiment, the setup, tentatively identified transitions, experimental CED and nuclear shell model predictions will be shown in this presentation. A preliminary interpretation of the experimental results will also be discussed.

[1] K. Wimmer, et al., Phys. Rev. Lett. 126, 072501 (2021).
[2] R.D.O. Llewellyn, et al., Phys. Lett. B 797, 135873 (2019).
[3] A. Boso, et al., Phys. Lett. B 797, 134835 (2019).
[4] B. Cederwall, et al., Nature 469, 6871 (2011).
[5] G.J. Fu, et al., Phys. Rev. C 87, 044312 (2013).
[6] Z.X. Xu, et al., Nucl. Phys. A 877 (2012) 51-58.

Speaker: Jesus Pereira-Lopez (University of York)

155-XPereiraLopez-Inbeamspectroscopyof94Ag.pdf

15:45 Investigation of limit of detection using standard radioactive sources with a LaBr3:Ce: detector

Keywords: LaBr3(Ce) detector; Background radiation; Gamma radiation; Detection limits

Abstract

NaI(Tl) detectors have for long been the preferred scintillation detector for radioisotope identification. However, one of the most profound shortcomings of this detector is its poor spectral resolution. A suitable replacement for NaI(Tl) is the LaBr3(Ce) detector. This detector shows significantly improved sensitivity and spectral resolution. This will be especially evident through measurements employing both peak and full-spectrum analysis.

During this study, an energy calibration of a LaBr3(Ce) detector was performed using radionuclides 22Na, 60Co and 152Eu as radiation sources. Ambient background radiation was measured with the intention of correction purposes after actual source measurements. The aforementioned sources have been measured at increasing distances from the detector. This study mainly focussed on the determination of the detection limits of each radiation source considering the presence of background radiation. Therefore, the change in the intensity measured for each source as a function of increasing distance from the detector has been emphasised. This application is in relation to the solid angle between the points of the radiation source and the active detector volume.

Studies and the application of all data available will focus on the relevant factors to calculate the limit of detection for a specific activity for each radiation source. Results obtained during the investigation indicated a relation between detector counts, solid angle, and source activity. Further studies and application of all data available will focus on the relevant factors to calculate the limit of detection for a specific activity for each radiation source.
This study forms part of a broader research project that entails the design, building and commissioning of a prototype mobile gamma-ray detection system equipped with a LaBr3(Ce) detector. The successful development of such a detector system will enable in situ measurements of radiation in various robust terrestrial environments with improved sensitivity and spectral resolution.

Speaker: Ferdie van Niekerk (Tshwane University of Technology)

174-F_van_Niekerk-Investigation_of_limit_of_detection_using_standard_radioactive-sources_with_a_LaBr3Ce_detector.pdf

Abstract SAIP 2021.pdf

15:45 Investigation of reaction channels in the production of alpha particles in light systems collisions

B. P. Monteiro, K. C. C. Pires, R. Lichtenthäler, O. C. B. Santos
Departamento de Física Nuclear, Instituto de Física, Universidade de São
Paulo, 05508-090, SP, Brasil

A study of the mechanisms involved in the production of alpha particles from
reactions induced by a 6He radioactive beam on a 9Be light target, is presented. The
experimental data was obtained using the RIBRAS (Radioactive Ion Beams in Brasil) facility
of the Institute of Physics of the University of São Paulo, Brazil [1, 2]. The RIBRAS system
consists of two superconducting solenoids used to select and focus light secondary beams of
nuclei far from the stability line. A high yield of α-particles has been observed in the
measurement performed for the 6He+9Be system [3], which was not present with the gold
target, used for normalization purposes. In the present work, the energy and the angular
distributions of those events have been analysed. The results will be compared with
theoretical calculations performed using the Ichimura-Austern-Vincent (IAV) formalism, a
new model recently applied to study inclusive reactions [4,5].
References
[1] R. Lichtenthäler Filho, A. Lépine-Szily, V. Guimarães. Eur. Jour. of Phys., 25, 733, 2005.
[2] A. Lépine-Szily, R. Lichtenthäler Filho, V. Guimarães. Nuclear Physics News, v. 23, p.
5-11, 2013.
[3] K. C. C. Pires et al, Phys. Rev. C83, 064603, 2011.
[4] Jin Lei, A. M. Moro. Phys. Rev. C92, 044616 (2015).
[5] O.C.B. Santos et al, Phys. Rev. C103, 064601 (2021).

Speaker: Bruno Penteado Monteiro (Instituto de Física da USP)

BrunoPMonteiro.pdf

BrunoPM_Poster.pdf

BrunoPM_Slides.pdf

15:45 Magnetic giant resonances in the relativistic energy density functional theory

Electromagnetic excitations in finite nuclei represent one of the most important probes of relevance in nuclear structure and dynamic. Various aspects of magnetic dipole (M1) mode have been considered due to their relevance for nuclear properties associated e.g., to unnatural-parity states and spin-orbit splittings. Specifically, M1 spin-flip excitations are analog of Gamow-Teller (GT) transitions, meaning that, at the operator level, the dominant M1 isovector component is the synonym to the zeroth component of GT transitions, and can serve as probe for calculations of inelastic neutrino-nucleus cross section essential in the r-process nucleosynthesis calculations.

In this work [2,3,4,5] we have introduced a novel approach to describe M1, $0^+$ ground state to $1^+$
excited state, transitions in even-even nuclei, based on the RHB + RQRPA framework
with the relativistic point-coupling interaction, supplemented with the pairing correlations described by the pairing part of the Gogny force. In addition to the standard terms of the point coupling model with the DD-PC1 parameterization, the residual R(Q)RPA interaction has been extended by the isovector-pseudovector $(IV-PV)$ contact type of interaction that contributes to unnatural parity transitions. This pseudovector type of interaction has been modeled as a scalar product of two pseudovectors. The strength parameter for this channel, $\alpha_{IV-PV}$ , is considered as a free parameter constrained by the experimental data on M1 transitions of $\rm^{48}Ca$ and $\rm^{208}Pb$ referent nuclei [2]. As analitical test, a newly developed sume rule for M1 transitions [1] has been applied, which confirmed results of our microscopical calculations [2]. Significance of pariring correlations has been demostrated on open shell nulclei $\rm^{42}Ca$ and especially $\rm^{50}Ti$ [2,5] where it has been reproduced two-peaked structure in a strength distribution expected from experimental spectrum in Ref.[6].
A recent experimental publication [7] investigates, by inelastic proton scattering, isotopic dependance of E1 and M1 strength distribution of even-even nuclei in $\rm ^{112-124}Sn$ isotope chain, that is why theoretically have been explored M1 transitions in Ref. [4] but over the wider isotope range $\rm ^{100-140}Sn$. As main results we would like to emphasize reproduced single and double-peaked structure in a strength spectra governed by single-particle evolution over $\rm ^{100-140}Sn$ isotope chain and significant reduction of spin-quenching $\zeta_s = g^{\sigma}_{eff}/g^{\sigma}_{free} = 0.80-0.93$ factor compared to the previous theoretical investigations. Indication in Ref. [6], that part of M1 strength above neutron threshold may be missing, leads to the conclusion that further experimental studies are required.

References:
[1] T. Oishi and N. Paar, Phys. Rev. C 100, 024308 (2019).

[2] G. Kružić, T. Oishi, D. Vale, and N. Paar, Phys. Rev. C 102, 044315 (2020).

[3] T. Oishi, G. Kružić, and N. Paar, J. Phys. G: Nucl. Part. Phys. 47 115106 (2020).

[4] G. Kružić, T. Oishi, and N. Paar, Phys. Rev. C 103, 054306 (2021).

[5] T. Oishi, G. Kružić and N. Paar, arXiv:2011.04676 (2020).

[6] D. I. Sober, B. C. Metsch, W. Knüpfer, G. Eulenberg, G.Küchler, A. Richter, E. Spamer, and W. Steffen, Phys. Rev. C 31, 2054 (1985).

[7] S. Bassauer et al., Phys. Rev. C 102, 034327 (2020).

Speaker: Goran Kružić (Ericsson-Nikola Tesla)

121-GKruzic_Magnetic_Giant_Resonances_in_RNEDF_Theory.pdf

15:45 New evidence for alpha clustering structure in the ground state band of $^{212}$Po

The isotope $^{212}$Po has two-protons and neutrons outside the doubly-magic nucleus $^{208}$Pb and it may be assumed that the nuclear structure can be well described within the standard shell-model. But various experimental properties, such as the short-lived ground state are inconsistent with this model and better predicted by an $\alpha$-clustering model. The B(E2) values of the decays of the low lying yrast-states are an important finger print to describe the structure of $^{212}$Po. Especially the missing B(E2; 4$_1^+ \rightarrow$ 2$^+_1$), and the corresponding missing lifetime of the 4$^+_1$ state, are important in this discussion.\
At the end of 2019, we had performed an experiment to determine the lifetime of the low-lying yrast states at the Bucharest FN Tandem accelerator in the Horia Hulubei National Institute for R\&D in Physics and Nuclear Engineering (IFIN-HH) in Magurele, Romania. $^{212}$Po were populated by an $\alpha$-transfer reaction between a $^{208}$Pb target and a stable $^{10}$B beam. The $\gamma$-rays from the excited states are detected at the ROSPHERE $\gamma$-ray detector array which consisted of 15 HPGe detectors and 10 LaBr$_3$(Ce) scintillator detectors. To detect coincidence particles, this setup was supplemented with the SORCERER particle detector system. The combination of $\gamma$-ray and the particle detectors was an important tool to determine the mean lifetimes of all ground state band levels up to the 8$^+$ state applying the fast-timing method.\
In this talk, I will present our lifetime analysis of the excited states of $^{212}$Po and will discuss the results within the shell-model and $\alpha$-clustering model.

Speaker: Martin von Tresckow (TU Darmstadt)

158-MvonTresckow-212Po-Poster.pdf

15:45 Nuclear matrix elements of neutrinoless double-β decay in the triaxial projected shell model

The nuclear matrix elements of neutrinoless double-beta decay for nuclei 76Ge, 82Se, 100Mo, 130Te, and 150Nd are studied within the triaxial projected shell model, which incorporates simultaneously the triaxial deformation and quasiparticle configuration mixing. The low-lying spectra, the B(E2: 0+ to 2+) values, and the occupancies of single-particle orbits are reproduced well. The effects of the quasiparticles configuration mixing, the triaxial deformation, and the closure approximation on the nuclear matrix elements are studied in detail. For nuclei 76Ge, 82Se, 100Mo, 130Te, and 150Nd, the nuclear matrix elements are respectively reduced by the quasiparticle configuration mixing by 6%, 7%, 2%, 3%, and 4%, and enhanced by calculating explicitly the transitions through odd-odd intermediate states by 7%, 4%, 11%, 20%, and 14%. Varying the triaxial deformation gamma from 0◦ to 60◦ for the mother and daughter nuclei, the nuclear matrix elements change by 41%, 17%, 68%, 14%, and 511% respectively for 76Ge, 82Se, 100Mo, 130Te, and 150Nd, which indicates the importance of treating the triaxial deformation consistently in calculating the nuclear matrix elements.

Speaker: Dr Yakun Wang (Peking University)

141-YK_Wang_poster-Nuclear matrix element of 0vbb in the triaxial projected shell model.pdf

15:45 Radiation Damage by Low Energy Neutrons with Geant4: A Review of Current Approaches and Results

Geant4 is a Monte Carlo based simulation toolkit utilized for the geometry and tracking of particles transport through matter. Geant4 offers variety of geometrical constructions, visualization, and multi-threading features, which are hard to find in simulating codes such as MCNP, FLUKA and FISPACTII. Evaluation of neutron radiation damage by means of Primary Knock-out Atoms (PKAs) and Displacements-Per-Atom (dpa) has been used to estimate damages in metals and semiconductor materials in which results have shown good agreement with experimental data. Recent evolution in Geant4 to include G4TENDL files especially with the enrichment of the Hadronic Physics List, promises improved results for low energy neutrons, making the toolkit more robust especially for simulating nuclear processes at low neutron energies (< 20 MeV) found in fission reactors. This work therefore reviews the radiation damage creation by low energy neutrons with Geant4, presenting it as a viable simulation tool for nuclear processes, considering the numerous advantages of this toolkit regarding speed, flexibility in data handling, geometry and its use of future programming languages in the simulation codes.
Keywords:Geant4, Radiation Damage, Neutron, Review.

Speaker: Samuel Terungwa Temaugee (School of Physics, University of the Witwatersrand, Johannesburg, South Africa)

168_ST_Temaugee_Radiation _Damage by Low Energy Neutrons with Geant4 A_Review of Current Approaches and Results.pdf

Abstract_ANPC2021_S.T.Temaugeenew1.pdf

15:45 Reaction processes at near barrier energies: the case of 9Be+197Au

Recent studies of nuclear reactions involving weakly bound stable nuclei, $^{6,7}$Li and $^{9}$Be have revealed several interesting phenomena [1]. The low breakup threshold, small binding energy, and cluster structure are some of the unique features of these nuclei, which strongly influence the reaction dynamics at near barrier energies. The simultaneous measurement of complete/ incomplete fusion and direct reactions (e.g. neutron transfer) can provide insight into the underlying mechanism. With this motivation, the excitation functions for complete fusion (CF), incomplete fusion (ICF), and transfer channels have been measured in $^{9}$Be+$^{197}$Au system, over the energy range 0.76 $\leq$ E$_{c.m.}$/V$_{\rm B}$ $\leq$ 1.16 (V$_{B}$ = 38.4 MeV). The experiment was carried out at the BARC-TIFR Pelletron-Linac Facility, Mumbai, India, by employing the stack-foil technique followed by offline gamma spectroscopy with two HPGe detectors. Theoretical model calculations using CCFULL and FRESCO codes are employed to interpret the measured cross-section data. The coupled channel calculations (CCFULL) successfully describe the data at sub-barrier energies and indicate $\sim$ 40$\%$ fusion suppression at above barrier energies [2]. Further, it is observed that amongst $\rm x$+$^{197}$Au systems, where x represents stable projectiles with Z = 2-5, the enhancement in sub barrier fusion is largest for $^{9}$Be. The ground state deformation of $^{9}$Be is shown to play an important role in sub barrier fusion along with the weak binding.
At sub barrier energies, the transfer process has been found to be dominant [3] in $^{9}$Be+$^{197}$Au, and the ratio of transfer to CF cross-sections is considerably higher in comparison to $^{6,7}$Li+$^{197}$Au systems. The CRC calculations for 1$n$-stripping ($^{198}$Au) highlight the role of 2+ resonance state of $^{8}$Be, as it provides better matching with the Q-value (4.85 MeV) of the reaction. The present studies indicate that observed differences amongst reactions with $^{6,7}$Li, $^{9}$Be can be attributed to the structural differences in these projectiles, and have also highlighted the impact of the large deformation as well as a spatial extension of $^9$Be nucleus. Details will be presented.

References

1. L.F. Canto et al., Phys. Rep. 424, 1 (2006); Phys. Rep. 596, 1 (2015) and the references therein.
2. Malika Kaushik et al., Phys. Rev. C 101, 034611 (2020).
3. Malika Kaushik et al., Arxiv: https://arxiv.org/abs/2104.13689.

Speaker: Malika Kaushik (Department of Physics, Indian Institute of Technology Ropar, Rupnagar - 140 001, Punjab, India)

160-M_Kaushik-Reaction_processes_at_near_barrier-energies_the_case_of_9Be+197Au.pdf

MKaushik_Abstract-ANPC2021.pdf

15:45 SIMSPEC-G: a new code for simulating the working of HPGe detectors

HPGe detectors are one of the most important components of experimental nuclear physics. Therefore, a deeper understanding of them is required for better utilization of the available resources. Simulations allow us to do that in a faster way while also pointing to unaccounted processes in case of a mismatch between simulated and measured spectra. While there exist many simulation routines to reproduce a spectrum, these are complicated as they are designed to have as few restrictions on the general setup, so as to cater to many detector materials and geometry. The new code SIMSPEC-G, being developed, is simple, fast and specific to HPGe detectors. In the beginning, we consider gamma photons $\leq$ 1 MeV, which interact with detector material through photoelectric and Compton interactions only. The interaction length is estimated using the energy dependent cross section data of the detector material obtained from the photon database at NIST [1]. SIMSPEC-G allows for tracking of gamma photons passing through the detector, storing the information about the type (Compton or photoelectric) and the point of interaction, energy lost, etc. This allows us to compute the energy spectra, the most probable energy deposited after the first interaction, distribution of different types of multiple scattering processes at different energies, efficiency, etc. Initially, we worked with a single crystal geometry, but later we extended the simulation to accommodate for clover geometry. We also worked out the effect of multi-segment events, due to clover geometry, on various parameters. The distribution of energy deposited in the first interaction segment in case of multi-segment events was also studied. Addback factor’s variation with incident photon energy is also estimated. Further details will be shared in the presentation.

REFERENCE

1. M. J. Berger, J. Hubbell, S. Seltzer, J. Chang, J. Coursey, R.
   Sukumar, D. Zucker and K. Olsen, "XCOM: Photon Cross Sections
   Database," 1 November 2020. [Online]. Available:
   www.nist.gov/pml/xcom-photon-cross-sections-database

Speaker: Satya Samiran Nayak (Variable Energy Cyclotron Center, India)

199-ss_nayak-SIMSPEC_G_a_new_code_for_simulating_the_working_of_HPGe_detectors.pdf

15:45 Spectroscopic studies in $^{152-154}$Gd

Fusion-evaporation reactions have been proven very successful in populating excited states of deformed nuclei. The rare-earth region has been the focus of various studies (using Coulex etc) aiming at the understanding of nuclear structure and providing information on the details of the reaction mechanism. The Gd isotopes belong to this group of nuclei and despite the available spectroscopic information, several open questions about their structure still exist, such as the interband transitions related to shape evolution or branching ratios in deformed states. In addition, production cross-sections of different reactions on Gd isotopes are largely unknown. In this work, we report on an experimental attempt to populate the excited states in the isotopes $^{152-154}$Gd, by employing the 2n transfer reaction $^{138}$Ba($^{18}$O, $^{16}$O)$^{140}$Ba and the subsequent fusion reaction $^{18}$O + $^{138}$Ba in the energy range of 61-67 MeV. The experiment was conducted at the 9 MV FV Pelletron Tandem at the Horia Hulubei National Institute for Physics and Nuclear Engineering (IFIN–HH), employing the ROSPHERE array. Several branching ratios for energy levels in $^{152,153}$Gd have been measured, offering data for the first time and updates of earlier measured values. Furthermore, relative cross-sections regarding the three Gd isotopes have been measured and compared with theoretical calculations from the PACE4 program.

Speaker: S. Pelonis (Department of Physics, National and Kapodistrian University of Athens)

117-S_Pelonis-Spectroscopic_studies_in_$^{152-154}$Gd.pdf

15:45 Studying the microscopic structure of the low-energy electric dipole response of $^{120}$Sn

The microscopic structure of the low-energy electric dipole response, commonly denoted as the Pygmy Dipole Resonance (PDR), was studied for $^{120}$Sn in a $^{119}$Sn$(d,p\gamma)^{120}$Sn experiment, using the SONIC@HORUS setup at the University of Cologne. Unprecedented access to the single-particle structure of excited $1^-$ states below and around the neutron-separation threshold was obtained by comparing experimental data to predictions from a novel theoretical approach. The approach combines detailed nuclear structure input from energy-density functional (EDF) plus quasiparticle-phonon model (QPM) theory with reaction theory to obtain a consistent description of both the structure and reaction aspects of the process. Similar to the recently investigated case of $^{208}$Pb [1], the combined results show that the EDF+QPM approach correctly predicts the energies of the relevant neutron single-particle levels in $^{120}$Sn and the fragmentation of the observed spectroscopic strength, and that the understanding of one-particle-one-hole structures of the $1^-$ states in the PDR region is crucial to reliably predict properties of the PDR. Furthermore, the EDF+QPM approach predicts the increasing contribution of complex configurations to the PDR states at higher excitation energies, which has been recently suggested as a cause for the discrepancy between $(\gamma,\gamma')$ and $(p,p')$ experiments [2,3]. This contribution will present the joint experimental and theoretical effort and discuss further applications, allowing a detailed study of the microscopic structure of the PDR along the isotopic chart.
[1] M. Spieker et al., Phys. Rev. Lett. 125, 102503 (2020)
[2] S. Bassauer et al., Phys. Rev. C 102, 034327 (2020)
[3] M. Müscher et al., Phys. Rev. C 102, 014317 (2020)

Speaker: Michael Weinert (University of Cologne, Institute for Nuclear Physics, 50937 Cologne, Germany)

Poster_Weinert.pdf

15:45 Triple RFQ Trap System for Measuring Neutron Capture of Fission Fragments

One of the current limitations of predicting the nuclear astrophysics r-process abundance is the lack of data on neutron-rich isotopes; measured neutron-capture cross-sections are the scarcest data. These cross-sections are also invaluable for nuclear reactions and structure in general. The current limitations come from the instability of the target and the projectiles. We proposed a method to overcome this limitation. The goal of this work is the selection and storage of fission fragments in a triple RFQ system. These stored ions will then be hit with an intense neutron beam. The reacted ions will then be ejected and measured using a multiple-reflection time-of-flight mass-spectrometer (MR-TOF-MS).

This poster will mainly focus on the RFQ-3 system that will be installed at Soreq Applied Research Accelerator Facility (SARAF-II)[1], currently under construction in Yavne, Israel. The existing RFQ-3 system [2] will be recommissioned and optimised for this project at Justus-Liebig-University Giessen, Germany. This recommissioning and optimisation will be presented as well as some of the future goals of the project.

[1] I. Mardor et al., Eur. Phys. Jour. A 54: 91 (2018)

[2] E. Haettner et al., Nucl. Instr. Meth. A 880, 138 (2018)

Speaker: Heinrich Wilsenach (Justus-Liebig-Universität Gießen)

154-H_Wilsenach-Triple_RFQ_Trap_System_for_Measuring_Neutron_Capture_of_Fission_Fragments.pdf

15:45 Unveiling the excitation modes of $^{28}$Si in interpreting the barrier distribution data

Abstract

Barrier distribution is a very sensitive tool for understanding fusion process in the presence of various possible channel couplings. There exist two experimental methods for investigating barrier distributions: (i) by the measurement of fusion excitation function and (ii) by the measurement of quasi-elastic excitation function. Among the two methods of measurements, the measurement involving category (ii) is relatively easier to carry out in the laboratory and provides additional advantages over the measurement under category (i). Our very recent published work [1,2,3] deals with quasi-elastic excitation function measurements (method (ii)) in and around the Coulomb barrier regime for the $^{28}$Si + $^{142,150}$Nd systems and the corresponding barrier distributions have subsequently been extracted. The data were collected simultaneously by a number of detectors at back-angles using narrow binning of incident beam energies. The experiment was carried out using the facilities available at IUAC, New Delhi. The experimental data have been interpreted invoking different possible channel couplings. Projectile excitations and ground state deformations (quadrupole as well as hexadecapole deformations) of the targets seem to play a dominant role in generating the observed barrier distributions. However, there remain unanswered questions about the low-lying excitation modes of the projectile, $^{28}$Si. Hence, extensive channel coupling calculations have further been undertaken. The ambiguities prevailing in the low-lying excitation modes of the projectile, $^{28}$Si will be highlighted in the conference following the results from detail channel coupling calculations and making comparisons of the barrier distribution data at the near barrier energies available for several systems involving $^{28}$Si projectile and other suitable targets.

References:
1. Saumyajit Biswas et al., Phys. Rev. C 102, 014613 (2020)
2. Saumyajit Biswas et al., Indian Journal of Pure & Applied Physics 58, 409-414 (2020)
3. Saumyajit Biswas et al., Proceedings of the DAE Symp. on Nucl. Phys. 64 (2019) 439 (http://www.sympnp.org/proceedings/)

Help and cooperation received from all the collaborators during the time of data taking and the follow up analysis process is gratefully acknowledged.

Speaker: Saumyajit Biswas (Department of Physics, Siksha Bhavana, Visva-Bharati University)

139-S_Biswas-Unveiling_the_excitation_modes_of_28Si_in_interpreting_the_barrier_distribution_data.pdf

Abstract_Saumyajit_Biswas.pdf

Tuesday, 21 September

09:45 → 11:15 Session 4: Nuclear Astrophysics

Convener: Fairouz Hammache (IJCLab Orsay)

09:45 Neutron capture cross section measurements for the astrophysical s-process

The slow neutron capture process (s-process) is responsible for producing about half of the elemental abundances between Fe and Bi in our cosmos. It occurs in low mass stars (1-5 solar masses) during their Asymptotic Giant Branch phase, and in massive stars during He core, and C shell burning. Neutron capture cross sections at stellar neutron energies are a key input for stellar models to predict abundances produced in the s-process. I will present recent results of cross section measurements and their astrophysical implications.

Speaker: Claudia Lederer-Woods

10:15 Nuclear Astrophysics with the K600 and the CAKE

The K600 magnetic spectrometer at iThemba LABS has been augmented over the last few years with various ancillary detectors for coincidence measurements. One of these ancillary detector arrays is the Coincidence Array for K600 Experiments (the CAKE) which consists of double-sided silicon strip detectors.

One of the mainstays of the experimental programme of the K600 and the CAKE has been nuclear astrophysics, in particular the measurement of decay modes from excited states in nuclei, populated in direct reactions using the K600. Recent highlights include the observation and characterisation of possible low-energy resonances in the $^{12}$C+$^{12}$C fusion reaction using the $^{24}$Mg($\alpha,\alpha^\prime$)$^{24}$Mg reaction, and a measurement of proton branching ratios in $^{22}$Mg populated with the $^{24}$Mg($p,t$)$^{22}$Mg reaction.

This talk will introduce the K600 and the CAKE and discuss some recent highlights from experimental studies.

Speaker: Philip Adsley (iThemba LABS/Wits)

10:35 Ferromagnetism in neutron matter

A neutron star is one of the possible end states of a massive star. It is compressed by gravity and stabilized by the nuclear degeneracy pressure. Despite its name, the composition of these objects are not exactly known. However, from the inferred densities, neutrons will most likely compose a significant fraction of the star’s interior. While all neutron stars are expected to have a magnetic field, some neutron stars ("magnetars") are much more highly magnetized than others: the inferred magnetar surface magnetic field is between $10^{14}$ to $10^{15}$ gauss.

While neutron stars are macroscopic objects, due to the extreme value of the stars' energy, pressure, and magnetic field the physics of the microscopic scale can be imprinted on the star's large scale behaviour. Hence a possible significant contribution to the superstrong magnetar magnetic field could come from a neutron ferromagnetic state in the magnetar interior.

This talk will focus on describing the thermodynamics of magnetized dense neutron matter, its equation of state, and possible observational implications for neutron stars.

Speaker: Jacobus Diener (Botswana International University of Science and Technology)

10:55 Nucleosynthesis in Novae and X-Ray Bursts – Open Issues

Classical novae are thermonuclear explosions that take place in the H-rich envelopes of accreting white dwarfs in stellar binary systems. The material piles up under degenerate conditions, driving a thermonuclear runaway. The energy released by the suite of nuclear processes operating at the envelope heats the material up to peak temperatures of 100 - 400 MK. During these events, about $10^{-7}$ – $10^{-4}$ solar masses, enriched in CNO and, sometimes, other intermediate-mass elements (e.g., Ne, Na, Mg, Al) are ejected into the interstellar medium. This suggests mixing between solar composition material transferred from the secondary and the outermost layers of the underlying white dwarf during the thermonuclear runaway. This paper explores a new methodology that combines 1D and 3D simulations. The early stages of the explosion (i.e., mass-accretion and initiation of the runaway) were computed with the 1D hydrodynamic code SHIVA. When convection extended throughout the entire envelope, the structures for each model were mapped into 3D Cartesian grids and were subsequently followed with the multidimensional code FLASH. Two key physical quantities were extracted from the 3D simulations and were subsequently implemented into SHIVA, which was used to complete the simulation through the late expansion and ejection stages: the time-dependent amount of mass dredged-up from the outer white dwarf layers, and the time-dependent convective velocity profile throughout the envelope. Implications for nova nucleosynthesis, with emphasis on $^7$Li, will be discussed.

A similar type of explosion, X-Ray Bursts (XRB), occurs in the envelopes of accreting neutron stars in stellar binary systems. The overall energy output in a typical XRB, $10^{39}$ erg, is released in a timescale between 10 - 100 s. Maximum temperatures during the explosion reach 1 GK, with a nuclear activity reaching species with atomic masses around A = 60 (and probably beyond). A major challenge in the modeling of XRBs is associated with the lack of observational nucleosynthetic constraints. It is unclear whether XRBs contribute to Galactic abundances because of the extremely large escape velocities from a neutron star surface. Indeed, the energy required to escape from the strong gravitational field of a neutron star of mass M and radius R is G M mp/R ∼ 200 MeV/nucleon, whereas the nuclear energy released from thermonuclear fusion of solar-like matter into Fe-group elements is only ∼ 5 MeV/nucleon. New results based on the coupling of hydrodynamic simulations and radiation-driven winds will be presented.

Speaker: Jordi Jose (UPC Barcelona)

11:15 → 11:30 Tea/Coffee/Short Break

11:30 → 13:30 Session 5: Nuclear Structure, Reactions and Dynamics

Convener: Nikolai Antonenko (BLTP, JINR)

11:30 Optical Spectroscopy of the Heaviest Elements

Following their discovery, great progress has been made in recent years in elucidating the atomic and nuclear properties of the superheavy elements, driven by the need to understand nuclear stability and how these atoms behave chemically.
Optical spectroscopy enables experimental exploration of the atomic structure of the elements and equally provides an alternative access to important nuclear properties, such as spins, moments, and changes in the mean squares of the charge radii. In this respect, however, the superheavy elements are still unexplored territory.
Even certain isotopes of fermium (Fm, $Z=100$), which can still be obtained in macroscopic quantities, are challenging for such studies, not to mention transfermium elements that can be produced only at in-flight separator facilities.
In recent decades, laser resonance ionization spectroscopy has emerged as the method of choice for initial atomic level searches and subsequent hyperfine spectroscopy in the region of the heaviest elements. The successful application of this method to the element nobelium (No, $Z=102$), has fueled efforts to study even heavier, more exotic radionuclides.
In this talk, I will present results from recent spectroscopy of $^{252-255}$No and $^{248-250,254,255,257}$Fm, followed by a brief outlook towards the spectroscopy of lawrencium ($Z=103$).

Speaker: Mustapha Laatiaoui (JGU)

12:00 Ab initio theory and the structure of heavy nuclei

Breakthroughs in our treatment of the many-body problem and nuclear forces are rapidly transforming modern nuclear theory into a true first-principles discipline. This allows us to address some of the most exciting questions at the frontiers of nuclear structure and physics beyond the standard model, such as the nature of dark matter and neutrino masses, as well as searches for violations of fundamental symmetries in nature.

In this talk I will briefly outline our many-body approach, the valence-space in-medium similarity renormalization group, and how recent advances now allows us to calculate converged properties of closed- and open-shell nuclei to the $^{208}$Pb region and beyond. In particular correlations of the neutron skin and dipole polarizability in heavy nuclei provide new constraints on symmetry energy parameters for determining neutron star properties. Finally, I will finally highlight new results for converged calculations of neutrinoless double beta decay and WIMP-nucleus scattering in heavy nuclei.

Speaker: Jason Holt (TRIUMF)

12:20 Statistical properties of the well deformed $^{153,155}$Sm nuclei and the scissors resonance

The rare-earth isotopic chain of Samarium provides an excellent opportunity to systematically investigate the evolution of nuclear structure effects from the near-spherical ($β_{2}$=0.00) $^{144}$Sm isotope to the well-deformed system ($β_{2}$=0.27) $^{154}$Sm. As the nuclear shape changes, statistical properties such as the nuclear level density (NLD) and $\gamma$-strength function ($\gamma$SF) are expected to be affected. In particular resonance modes, such as the Pygmy Dipole (PDR), Scissors Resonances (SR), and the recently discovered Low-Energy Enhancement (LEE) in the rare-earth region may reveal interesting features when their evolution is investigated across several nuclei in an isotopic chain. An experiment was performed at Oslo Cyclotron Laboratory (OCL) where the NaI(Tl) $\gamma$-ray array and silicon particle telescopes were utilized to measure particle-$\gamma$ coincidence events from which the NLDs and $\gamma$SFs have been extracted below the neutron threshold, Sn, using the Oslo Method (A. Schiller et al., 2000). The deuteron beam was used to populate excited states in $^{153,155}$Sm through transfer reaction (d,p$\gamma$). Based on the results from these measurements, the extracted NLDs and $\gamma$SFs have been used to investigate the evolution of nuclear structure effects, in particular the SR, in $^{153,155}$Sm. In this talk, I will present results of statistical properties for $^{153,155}$Sm and compare them to previous measurements of $^{148,149}$Sm and $^{151-154}$Sm.

This work is based on the research supported in part by the National Research Foundation of South Africa (Grant Number 118846) and by the IAEA under Research Contract 20454.

Speaker: Kgashane Malatji (iThemba LABS)

12:40 Coexistence of single-particle and collective structures in 1f $_{7/2}$ nuclei

Nuclei in $A\sim50$ region that are close to the line of stability and have ($1f_{7/2}$)$^{n}$ ground state configuration for both proton and neutron, were investigated. Particularly, $^{51}Cr$ (Z =24) and $^{50}V$(Z =23) are of special interest as the proton $1f_{7/2}$ is only about half-occupied, but number of neutrons in neutron $1f_{7/2}$ orbital is just one short of the shell closure. The proton configuration is expected to induce collective behavior while the neutron configuration should lead to a single-particle structure. Hence these nuclei provide a fertile ground for studying the interplay of collective and single-particle effects. Two different experiments employing $^{27}Al$( $^{28}Si$, 3$p1n$)$^{51}Cr$ and $^{48}Ti$($α$, $pn$)$^{50}V$ reactions were carried out at Tata Institute of Fundamental Research, Mumbai, India and Variable energy Cyclotron Centre, Kolkata, India to investigate the level structures of these nuclei.

Earlier work on $^{50}V$ level scheme dates back to the sixties and seventies decade that were carried out with a modest number of Ge(Li) detectors[ 1, 2]. The latest work on $^{51}Cr$ nucleus was reported in the beginning of the decade of nineties employing only five HPGe detectors [3]. The present experimental setups consisted of large clover detector arrays (INGA: Indian National Gamma Array), and this has led to considerable extension in the level scheme of both of these nuclei. The level schemes mostly reveal irregular spacing of the levels and follow shell model pattern. However deformation, though not substantial, has been considered in the interpretation of non-yrast bands. Particularly both show a non-yrast band decaying to the ground state along with the yrast band. In $^{51}Cr$, long-elusive fast feeding transitions to certain yrast states have been observed. Lifetimes of these states have been extracted employing DSAM technique. Large Scale Shell Model (LSSM) calculations using NuShellX @MSU[4] code has been carried out for both the nuclei in the full $fp$ valence space in the present work, unlike the previous calculations that restricted the number of particle excitations. Experimental results, theoretical calculations and their interpretations will be presented in detail during the conference.

[1] A. Giorni et al., Nucl. Phys. A 292 (1977) 213
[2] D. L Kennedy et al., Nucl. Phys. A 293 (1977) 150
[3] J. A. Cameron etal., Phys. Rev. C 44 (1991) 2358
[4] B. A Brown and W. D. M Rae, Nucl. Data Sheets 120 (2014) 115

Speaker: Ritwika Chakrabarti (Department of Physics, University of Mumbai, Mumbai, India)

13:00 Isospin dependence of NN correlations, quenching of spectroscopic factors, and effects on other nuclear structure observables

Although the atomic nucleus consists of strongly interacting nucleons, it is noteworthy that for such strongly interacting quantum system the independent-particle model is proven to be a valid approximation and has provided a basic framework to explain many properties of nuclei. However, correlations between the nucleons, both of short- and long-range nature, modify the mean-field approximation and dilute the pure independent-particle picture. Notably, these correlations are thought to be the reason for the quenching of spectroscopic factors observed in (e,e’p), (p,2p) and single-nucleon direct reactions [1]. Following from the observed increase of the high-momentum component of the proton momentum density in a neutron-rich nucleus [2], we proposed a phenomenological approach to examine the role of NN short- and long-range correlations and their evolution in asymmetric systems [3]. The model predictions correlate well with the reduced proton occupancies for states below or near the Fermi level [4,5], as a function of the asymmetry (N-Z)/A, and also shed light on the question of quenching in intermediate energy single-nucleon knockout on complex targets [6].

In this talk I will discuss our work [3] and further implications of our approach to other low-energy nuclear structure observables.

[1] W. Dickhoff and C. Barbieri, Prog. Part. Nucl. Phys. 52 (2004) 377.
[2] M. Duer et al., Nature 560 (2018) 617.
[3] S. Paschalis, M. Petri, A.O. Macchiavelli, O. Hen, and E. Piasetzky, Phys. Lett. B 800 (2020) 135110.
[4] G. Kramer, H. Blok and L. Lapikas, Nucl. Phys. A 679 (2001) 267.
[5] L. Atar et al., Phys. Rev. Lett. 120 (2018) 052501.
[6] J. A. Tostevin and A. Gade, Phys. Rev. C 103 (2021) 054610.

Speaker: Marina Petri (University of York)

13:30 → 14:00 Meal/Long Break

14:00 → 16:15 Workshop Session 1: What new directions could stable ion beams and novel instrumentation bring to further our understanding of exotic shapes, exotic nuclei and exotic decay modes?

Convener: Adam Maj (IFJ PAN Krakow)

14:00 A selection of “exotic” nuclear states: stretched, near threshold and shape-isomer-like states

Speaker: Silvia Leoni (INFN)

14:25 Q&A with Discussion

Speaker: Adam Maj (IFJ PAN Krakow)

14:35 Probing collective excitation modes of nuclei with stable beams using gamma and particle detector arrays

Speaker: Rudrajyoti Palit (TIFR)

15:00 Q&A with Discussion

Speaker: Adam Maj (IFJ PAN Krakow)

15:10 Tea/Coffee/Short Break

15:25 Decay Spectroscopy of Superheavy Elements

Speaker: Daniel Cox (Lund University)

15:50 Q&A with Discussion

Speaker: Adam Maj (IFJ PAN Krakow)

16:00 Summary Discussion

Speaker: Adam Maj (IFJ PAN Krakow)

Wednesday, 22 September

09:25 → 09:45 Session 3 Continued: Mixed Topics

Convener: Sotirios Charisopoulos (IAEA)

09:25 The Felsenkeller accelerator for nuclear astrophysics

Nuclear astrophysics often relies on small cross sections in the region of fusion reactions. Hence, the reaction rates are small. Over the last decade we were able to install a 5 MV tandem accelerator underground in Dresden (Germany) for this purpose. The facility is meant to be open for all scientists to use, proposals will be evaluated by an external committee. For the measurements proton, helium and carbon beams are available.
The talk will present the new facility and the dedicated measurements
on background studies. Additional detectors are installed, among them for example an ultra-low background with high detection efficiency. Furthermore,
in the talk first scientific results will be presented.

Speaker: Kai Zuber (TU Dresden)

09:45 → 11:15 Session 6: Nuclear Astrophysics

Convener: Angela Bracco (Università di Milano e INFN)

09:45 Nuclear physics and r-process observables

Our understanding of the formation of the heaviest elements via r-process nucleosynthesis is built up through the detection and analysis of a variety of astrophysical observables: isotopic and elemental abundance patterns, electromagnetic signatures, and radioisotopes. The interpretation of each type of observable is complicated by the unknown nuclear physics of the thousands of neutron-rich species that participate in the r process. Here we will describe a few examples of how r-process observables can be exploited to provide clues as to the nature of r-process site(s) of production, and note how current and upcoming experiments at radioactive beam facilities can provide crucial data and fresh insight.

Speaker: Rebecca Surman (University of Notre Dame)

10:15 Radiative proton-capture cross-sections with $^{112,114}$Cd

The reaction network in the neutron-deficient part of the nuclear chart around A~100 contains several nuclei of importance to astrophysical processes, such as the p-process. This work reports on the results from recent experimental studies of the radiative proton-capture reactions $^{112,114}$Cd(p,γ)$^{113,115}$In. Isotopically enriched $^{112}$Cd and $^{114}$Cd targets have been used for the determination of the cross sections, for proton beam energies residing inside the respective Gamow windows for each reaction. Two different techniques, the in-beam γ-ray spectroscopy and the activation method have been implemented, where the latter is considered mandatory to account for the presence of low-lying isomers in $^{113}$In and $^{115}$In, with energies of E≈392 keV, and E≈336 keV, respectively. Following the measurement of the cross sections, the astrophysical S factors have been subsequently deduced. The experimental results are compared to detailed Hauser-Feshbach theoretical calculations carried out with TALYS v1.95.

Speaker: Polytimos Vasileiou (National and Kapodistrian University of Athens)

ANPC_talk_122_PVasileiou.pdf

10:35 Investigation of the dipole response of 64Ni in real-photon scattering experiments

One of the two main nucleosynthesis processes for explaining the formation and abundances of the neutron-rich nuclei in our universe is the slow neutron-capture process (s process). It takes place in environments with neutron densities in the range of 10$^{6}$–10$^{12}$ cm$^{−3}$. Due to these relatively small neutron densities, the β- decay rate usually dominates over the neutron-capture rate and, hence, the s-process reaction path follows the valley of stability. At a so-called branching-point nucleus, the aforementioned reaction rates become competing and the reaction path branches. One of these branching-point nuclei is $^{63}$Ni. Its radiative neutron-capture cross section is crucial for determining the corresponding branching ratio. Therefore, $^{63}$Ni(n,γ) experiments have been performed [1,2]. But, the determined cross sections take only radiative-neutron captures on $^{63}$Ni nuclei in the ground state into account and neglect that a certain amount is excited in stellar environments [3]. Hence, theoretical corrections have to be applied using, e.g., Statistical Hauser-Feshbach calculations [4]. For these, the Photon Strength Function (PSF) is one input parameter which is closely related to the photoabsorption cross section which can be deduced from real-photon scattering experiments.
Furthermore, systematic studies of the photoabsorption cross section can be utilized to investigate the properties of dipole excitation modes. For instance, in many nuclei an accumulation of electric dipole strength below and around the neutron separation threshold has been observed which is commonly denoted as Pygmy Dipole Resonance (PDR) [5]. During the last two decades, experimental and theoretical effort was put into the investigation of the PDR. Nevertheless, there are still some open questions concerning this excitation mode and systematic studies are crucial. Due to the wide range of N/Z ratios of stable, even-even nuclei, the nickel isotopic chain is well suited for this purpose. Real-photon scattering experiments have already been performed on $^{58,60,62}$Ni [6-8] and the dipole responses of the unstable isotopes $^{68,70}$Ni have been measured using relativistic Coulomb excitation in inverse kinematics [9-11]. Therefore, the missing link for completing this systematic investigation is $^{64}$Ni.
Two complementary real-photon scattering experiments on $^{64}$Ni were performed using a continuous bremsstrahlung and a quasi-monoenergetic photon beam to obtain the total and absolute photoabsorption cross section in a model-independent way. In this contribution, the corresponding experiments and preliminary results will be presented.
This work is supported by the BMBF (05P18PKEN9).

[1] C. Lederer et al., Phys. Rev. Lett. 110, 022501 (2013)
[2] C. Lederer et al., Phys. Rev. C 89, 025810 (2014)
[3] T. Rauscher, Astrophys. J. Lett. 755, L10 (2012)
[4] W. Hauser and H. Feshbach, Phys. Rev. A 87, 366 (1952)
[5] D. Savran et al., Phys. Rev. C 84, 024326 (2011)
[6] F. Bauwens et al., Phys. Rev. C 62, 024302 (2000)
[7] M. Scheck et al., Phys. Rev. C 87, 051304(R) (2013)
[8] M. Scheck et al., Phys. Rev. C 88, 044304 (2013)
[9] O. Wieland et al., Phys. Rev. Lett. 102, 092502 (2009)
[10] D.M. Rossi et al., Phys. Rev. Lett. 111, 242503 (2013)
[11] O. Wieland et al., Phys. Rev. C 98, 064313 (2018)

Speaker: Miriam Müscher (Institute for Nuclear Physics, University of Cologne)

10:55 Experimental Study of the 30Si(p,γ)31P via the 30Si( 3He,d)31P transfer reaction for understanding elemental anomalies in Globular Clusters.

Globular clusters are key grounds for models of stellar evolution and early stages of the formation of galaxies. Abundance anomalies observed in the globular cluster NGC 2419, such as the enhancement of potassium and depletion of magnesium [1] can be explained in terms of an earlier generation of stars polluting the presently observed stars [2]. However, the nature and the properties of the polluting sites are still debated. The range of temperatures and densities of the polluting sites depends on the strength of a number of critical thermonuclear reaction rates. The $^{30}$Si($p$,$\gamma$)$^{31}$P reaction is one of the few reactions that have been identified to have an influence for elucidating the nature of polluting sites in NGC 2419 [3]. The current uncertainty on the $^{30}$Si($p$,$\gamma$)$^{31}$P reaction rate has a strong impact on the range of possible temperatures and densities of the polluter sites.

Hence, we investigated the $^{30}$Si($p$,$\gamma$)$^{31}$P reaction with the aim to reduce the associated uncertainties by determining the strength of resonances of astrophysical interest. In this talk I will present the study of the reaction $^{30}$Si($p$,$\gamma$)$^{31}$P that we performed via the one proton $^{30}$Si($^{3}$He,$d$)$^{31}$P transfer reaction at the Maier-Leinbnitz-Laboratorium Tandem. With the high resolution Q3D magnetic spectrograph, we measured the angular distributions of the light reaction products. These angular distributions are interpreted in the DWBA (Distorted Wave Born Approximation) framework to determine the proton spectroscopic factor information needed to determine the proton partial width of the states of interest. This information was used to calculate the $^{30}$Si($p$,$\gamma$)$^{31}$P reaction rate. The uncertainties on the reaction rate have been significantly reduced and key remaining uncertainties have been identified.

Bibliography

[1] C. Iliadis, A. I. Karakas, N. Prantzos, J. C. Lattanzio, and C. L. Doherty, “On Potassium and Other abundance Anomalies of Red Giants in NGC 2419,” The Astrophysical Journal, vol. 470, p. 98, Feb. 2016.

[2] R. G. Gratton, E. Caretta, and A. Bragaglia, “Multiple populations in globular clusters. Lessons learned from the Milku Way globular clusters,” The Astronomy and Astrophysics Review, vol. 20, p. 50, Feb. 2012.

[3] J. R. Dermigny and C. Iliadis, “Sensitivity to Thermonuclear Reaction Rates in Modeling Abundance Anomalies of NGC 2419,” The Astrophysical Journal, vol. 848, p. 14, Oct. 2017.

Speaker: Djamila Sarah Harrouz (Université Paris-Saclay, CNRS/in2p3, IJCLab)

11:15 → 11:30 Tea/Coffee/Short Break

11:30 → 13:30 Session 7: Neutron and Applied Nuclear Physics

Convener: Andy Buffler (UCT)

11:30 A Study of Environmental Radioactivity Measurement of selected Kaolin Mining Fields in Kwara, Nigeria

This article reports in-situ measurements of the gamma dose rates and the activity concentrations 238U, 232Th and 40K, at about 1m above earth over kaolin mining fields in Ilorin-south and Ilorin-west, Kwara, Nigeria. A calibrated high precision and great accuracy RS-125 Super-Spec gamma spectrometer was utilized to perform radioactivity measurements on both minefields. Readings were recorded in 90 randomly selected sample points. For Ilorin-south mining site, 50 sample points were recorded together with their standard error while 40 randomly selected sample points were considered for Ilorin-west mining site. Descriptive statistical investigations of the results were carried out to examine the statistical correspondences between the measured quantities. The results of the activity concentrations showed that the locations are enhanced with 40K compared with 238U and 232Th. The mean values of the estimated radiological hazard parameters are mostly within the recommended global averages. The measured outcomes are presented for further evaluation that can offer understandings on the state of radiological risks of Fufu, Akerebiata and their environments from the perspective of radiation protection. The results in this current work can be used as a significant baseline radioactivity data of these mining fields for future epidemiology and monitoring purposes.

Speaker: Mojisola Rachael Usikalu (Covenant University)

ANPC 2021 Abstract 2_Usikalu.docx

12:00 Development of a digital data acquisition system for neutron metrology

Development of a digital data acquisition system for fast neutron metrology

University of Cape Town (UCT): C. Sole, A. Buffler, T. Hutton, T. Leadbeater
Institut de radioprotection et de sûreté nucléaire (IRSN): V. Gressier, R. Babut, M. Petit

Fast neutron fields are found in a wide variety of contexts, for example at accelerator and medical radiation facilities, around nuclear power plants, in aviation and space flight. The essence of neutron metrology is to quantify both the fluence and energy distribution of these fields, which is complicated by the large range of energies, intensities and directional characteristics in each unique scenario [1]. Neutron metrology and spectrometry communities are beginning to adopt modern digital pulse processing systems to complement, and eventually replace, the existing analogue data acquisition systems [1,2].

Digital pulse processing electronics offer several distinct advantages over the existing analogue systems, with a need to rigorously benchmark against the current metrology standards prior to deployment [3]. Measurements were made using a BC-501A scintillator detector for neutron fields with energies between 1.2 MeV and 20.0 MeV over the full range of available beam currents at the AMANDE fast neutron metrology facility [4] at the IRSN. Comparisons were made between the AMANDE standard analogue data acquisition system, and a new digital system comprised of a CAEN DT5730 digitizer and the open source QtDAQ software [5]. An overview of the comparison will be presented, with a focus on the definition of the digital light output parameter, and dead time effects. Based on these measurements, recommendations will be made for implementing a fully digital data acquisition system for fast neutron metrology.

[1] D. Thomas et al. (2011) Metrologia 48 S225.
[2] V. Fedorov et al. (2018) EPJ Web of Conferences. 170 02005.
[3] A. Buffler et al. (2016) Int. J. Mod. Phys. 44 1660228.
[4] V. Gressier et al. (2004) Rad. Prot. Dos. 110 49.
[5] A. Comrie et al. (2015) NIMA 772 43.

Speaker: Chloe Sole (UCT)

Chloe-ANPCAbstract-2021_submitted.docx

12:20 The South African Space Neutron Initiative (SASNI)

Cosmic radiation consisting of Galactic Cosmic Rays (GCRs) and Solar Energetic Particles (SEPs), and their associated secondary particles are a known radiation hazard for high altitude flights, satellites, and space operations. Solar energetic particles result from highly unpredictable space weather events, releasing a large number of high energy protons and alpha particles over short periods of time.

Cosmic ray interactions with matter produce a cascade of secondary particles, consisting of electrons, mesons, pions, protons, neutrons, alpha particles and higher mass fragments. At aviation altitudes around 40% of the total dose equivalent from this complex radiation field is attributed to neutrons with energies between 1 and 100 MeV, which poses the greatest challenge for dosimetric systems. Dosimetry at flight altitudes continues to grow in importance due to the increased awareness of the exposure of air crew personnel to cosmic radiation. This topic is of special importance because the accumulated effective dose of a significant number of air crew members will be between 1 mSv and 5 mSv per year, receiving the largest exposures of all occupationally exposed persons. The equivalent dose in the atmosphere strongly depends on geomagnetic latitude and altitude, and there have been few experimental measurements made in the Southern Hemisphere.

In general, there is a lack of experimental data for high-energy neutrons (> 20 MeV), and as such there is insufficient information regarding the biological effects and severity of neutron interactions to make accurate risk assessments. In order to improve understanding of radiobiological observations related to high-energy neutron irradiation, it is critical to fully characterize these mixed fields at the point of interest.

The South African Space Neutron Initiative (SASNI) is a new research collaboration between the Metrological and Applied Sciences University Research unit (MeASURe) at the University of Cape Town, the South African National Space Agency (SANSA) and the Radiation Biophysics division at iThemba LABS. The collaboration has a broad focus on the measurement of secondary neutrons produced by cosmic rays and the radiation protection consequences which follow, particularly regarding South African civil aviation and space missions.

Speaker: Tanya Hutton (University of Cape Town)

240-T_Hutton-SASNI.mp4

12:40 Are LaBr3:Ce detectors the optimum instruments for naturally occurring radioactive materials (NORM) activity measurements?

LaBr$_3$:Ce (2" x 2") detectors were used to measure soil samples placed in Marinelli beakers in singles and coincidence modes. Time-stamped data were acquired and background removed offline by using photon time-of-flight in addition to measurement of the two photon energies in coincidence. Coincident gamma-ray pairs from $^{238}$U ($^{214}$Bi) and $^{232}$Th ($^{208}$Tl) series were identified in measured samples. The activity concentrations of $^{238}$U and $^{232}$Th series radionuclides inside the samples were determined in both singles and coincidence modes. The internal activity of the LaBr$_3$:Ce detector increases the MDA at 1460.8 keV and 2614.5 keV, which limits the measurement of $^{40}$K radionuclide with low activity concentration in singles mode. The measured internal activity of $^{138}$La in the LaBr$_3$:Ce detector crystal is 263.8 $\pm$ 26.8 Bq kg$^{-1}$ which is comparable to the calculated activity of 293.3 Bq kg$^{-1}$. The suitability of the use of these detectors for NORM measurements was evaluated.

Speaker: Munirat Bashir ( Ibrahim Badamasi Babangida University )

Abstract_ANCP.pdf

13:00 Advances in radon research and protection in Cameroon

Indoor radon measurements started in Cameroon since 2012 by measuring 222Rn using the Electret Ionization chambers (EIC) in about 500 dwellings of some ore bearing areas, followed by the discriminative measurements of 222Rn and 220Rn in 450 dwellings using RADUET detectors in some mining and ore bearing areas of Cameroon. The collected data helped to build a Technical Cooperation Project with the International Atomic Energy Agency (IAEA) on establishing a national radon plan for controlling public exposure due to radon indoors. A total of 1500 RADTRAK detectors to measure 222Rn were deployed in the whole country, collected and analyzed. The results of indoor radon measurements and inhalation dose assessment showed the importance to put in place radon regulation and national radon action plan. Radon regulation was drafted and the national radon action plan adopted in October 2020. The priority tasks for 2022-2025 are radon-risk mapping, radon mitigation, radon-risk communication and the integration of radon issue in the training of building professionals.

222Rn, 220Rn and 220Rn progeny measurements confirmed the importance to consider 220Rn in dose assessment to avoid biased results in epidemiological study. At the international scale, reference levels should be defined for 220Rn as done for 222Rn some decades ago. Effective dose due to 220Rn determined from the equilibrium factor is unreliable. Therefore, the risk of public exposure due to 220Rn and its progeny may therefore be higher than that of 222Rn and its progeny in many parts of the world if the equilibrium factor of 220Rn is no longer used in estimating total effective dose. It is therefore important to directly measure 222Rn and 220Rn progenies for a correct estimate of effective dose.

Uncertainty assessment in biokinetic and dosimetric models of α, β, αγ, βγ -emitters for ingestion and inhalation dose coefficients was carried out followed by the determination of the inhalation dose coefficients of 219Rn progeny, stemming from the disintegration of 223Ra used in nuclear medicine to treat bone metastasis due to prostate cancer.

Speaker: Saïdou - (Research Centre for Nuclear Science and Technology)

229-S_Saidou_My_Invited_Talk.pptx

13:30 → 14:00 Meal/Long Break

14:00 → 15:25 Workshop Session 2: What new directions could stable ion beams and novel instrumentation bring to further our understanding of Nuclear Astrophysics?

Convener: Augusto Macchiavelli (Lawrence Berkeley National Laboratory)

14:00 Photon Strength Functions: Prospects for Nucleosynthesis and Nuclear Structure Studies

Speaker: Mathis Wiedeking (iThemba LABS)

14:25 Q&A with Discussion

Speaker: Augusto Macchiavelli (Lawrence Berkeley National Laboratory)

14:35 Novel Techniques for Understanding Reactions Critical to Astrophysics

Speaker: Kelly Chipps (ORNL)

15:00 Q&A with Discussion

Speaker: Augusto Macchiavelli (Lawrence Berkeley National Laboratory)

15:10 Summary Discussion

Speaker: Augusto Macchiavelli (Lawrence Berkeley National Laboratory)

Thursday, 23 September

09:45 → 11:15 Session 8: Neutron Physics, Nuclear Structure, Reactions and Dynamics

Convener: Hiroyoshi Sakurai (RINE Nishina Center)

09:45 The Neutrons For Science Facility of GANIL/SPIRAL2

The neutrons for science facility (NFS) is the first operational experimental area of the new GANIL/SPIRAL2 facility. It is composed of two main areas: a converter room where neutrons are produced and activation measurements are performed, and a 28-meters long time-of-flight area where high neutron-energy resolution is achieved by the time-of-flight technique.
NFS benefits from the intense proton and deuteron beams delivered by the LINAC of SPIRAL2 in order to produce neutron beams in the range of 1-40 MeV through reactions in Be and Li converters. The NFS commissioning started in the fall of 2020 were proton-induced reaction cross-sections as well as neutron beam characteristics were measured. The second phase of the commissioning, using deuteron beams, is scheduled for this year as well as the first accepted experiments.
The first results, showing the capability of the facility, will be presented and compared with previous data. The future physics cases and the first experiments to run at NFS will be presented as well.

Speaker: Diego Ramos (GANIL)

10:15 Search for $E$0 transitions in $^{54}$Mn via electron-pair spectroscopy

The low energy structure of nuclei close to the doubly magic $^{40}$Ca and $^{56}$Ni are driven by collective excitations, including shape coexistence and super-deformation [1]. On the other hand, the N=28 shell closure is also strongly influencing the nuclei between N=Z=20 and 28. Electric monopole, $E$0 transitions are often cited as excellent probes to explore the interactions of collective excitations with different deformations. Strong $E$0 transitions are reported in $^{54}$Fe [2] and in $^{52}$Cr [3], however most of the $E$0 transitions in the region has not been observed. We shall report on a detailed conversion electron and electron-positron pair conversion study of $^{54}$Mn, a N=29, Z=25 nucleus next to $^{52}$Cr and $^{54}$Fe. Excited states up to about 3 MeV energy have been populated using the $^{54}$Cr(p,n)$^{54}$Mn reaction at 5.4 MeV bombarding energy at the ANU HIAS accelerator. Electron and electron-positron pair conversion coefficients have been measured with the Super-e spectrometer [4]. The 1579 keV transition from the 1634 keV 2$^{+}$ state has a conversion coefficient larger than the pure $M$1 or $E$2 value, indicating a significant $E$0 contribution. In this talk we describe the experiments and will present a preliminary interpretation of the results.

[1] K. Hyde and J.L. Wood, Rev. Mod. Phys. 83 (2011) 1467
[2] T.K. Eriksen, PhD thesis, ANU (2018)
[3] J.T.H. Dowie, PhD thesis, ANU (2021)
[4] T.K. Eriksen et al., Phys. Rev. C 102 (2020) 024320

Speaker: Abraham Avaa (iThemba/Wits)

171_AA.Avaa_Search_E0_vs1.mp4.mp4

171_AA.Avaa_Search_E0_vs2.mp4.mp4

171_AA.Avaa_Search_For_E0.mp4

ANPC2021.pdf

10:35 Analysis of fission yield measurements from $^{236}$U* using prompt $\gamma$-ray spectroscopy: Challenges, Anomalies, and Resolutions

Prompt $\gamma$-ray spectroscopy is one of the experimental approaches that can effectively be utilized for extracting the relative isotopic and mass yield distributions of the fission fragment nuclei, produced from the compound fissioning nucleus. Ideally, this is a novel technique, in the sense, that it can be used to measure accurate fission yield distributions with one unit of mass resolution. However, one has to deal with several difficulties while analyzing the in-beam fission fragment spectroscopic data. These difficulties are related to several factors, such as the unwanted contributions from beta-decay precursors, presence of isomeric states in the low-lying yrast band of the fragment nuclei, presence of close-lying transitions in the fragment nuclei, underestimation of $\gamma$-ray yields due to the accompanying electron conversion processes, etc. Hence, one has to properly optimize the analysis procedure for unambiguous extraction of the fission fragment yields from the coincidence $\gamma$-ray spectrum. Such an optimization in the analysis procedure has been followed for in-depth analysis of the in-beam fission fragment spectroscopic data obtained from two separate experiments: (i) thermal neutron-induced fission of $^{235}$U during the EXILL campaign [1] at Institut Laue-Langevin (ILL), Grenoble, France, and (ii) alpha-induced fission of $^{232}$Th during the INGA campaign [2] at Variable Energy Cyclotron Centre (VECC), Kolkata, India. It is to be noted that the compound fissioning nucleus was $^{236}$U* in both the measurement, albeit the excitation energy was slightly higher in the latter. The analysis procedure in detail, highlighting the challenges and approaches that were adopted to address those, will be presented at the conference. The important results that have been obtained from the analysis of the two sets of data will also be discussed.

The Indian National Gamma Array (INGA) and EXILL collaborations are duly acknowledged. Help and support from the Cyclotron operation staffs (at VECC, Kolkata), as well as the reactor operation staffs (at ILL, Grenoble) are thankfully acknowledged. This is a part of the work carried out with the financial assistance from the DAE-BRNS, Government of India [Project Sanction No. 37(3)/14/17/2016-BRNS].

References:
1. Aniruddha Dey et al., Phys. Rev. C 103, 044322 (2021)
2. Aniruddha Dey et al., Proc. of the DAE Symposium on Nucl. Phys. 101, 268 (2018) [URL : http://www.sympnp.org/proceedings/63/A101.pdf]

Speaker: Aniruddha Dey (1) Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India, 2) Department of Physics, Siksha Bhavana, Visva-Bharati University, Santiniketan, West Bengal 731 235, India)

140-AN_Dey_Fission_Yield_Measurement.mp4

ANPC_abstract_2021.pdf

10:55 Overlap integrals in core + n + n systems

Di-neutron correlations are extensively explored in recent experiments, and the enhancement of the spatial localization of the pair of the neutrons (n) has been confirmed at the nuclear surface in the light neutron-excess systems, such as $^{11}$Li and $^{19}$B. The di-neutron correlations are also investigated theoretically by employing the three-body model with core + n + n. The analysis of the di-neutron correlation gives an important key to elucidate the intrinsic structure of neutron stars. If we consider the three-body system of core plus two neutrons, the spatial localization of two neutrons corresponds to the formation of “di-neutron cluster” around the core nucleus.

On the other hand, the valence neutrons usually perform the independent particle motion around the core nucleus, and the ground state of the normal nucleus is explained by the so-called the nuclear shell model. The shell model configuration and the di-neutron one seem to be very different structure intuitively but these two configurations are non-orthogonal, and there is a finite amplitude of the di-neutron cluster component even if the pure shell model state is realized. Thus, in order to understand the feature of the di-neutron cluster more deeply, it is important to evaluate the overlap integral of the di-neutron cluster state and the shell model state, which is a measure of the non-orthogonal amplitude of these two different states.

We have proposed a new formula to evaluate the overlap integral of the cluster and shell-model configurations, and the formula is applied to the core + n + n systems. In this report, we will report the systematic feature of the overlap integrals of the di-neutron cluster state (core + 2n) and the shell model state (core + n + n) with a variation of the core mass number. In particular, we will discuss the enhancements of the overlap integral in connection to the single particle orbits of the valence two neutrons in the shell model states.

Speaker: Makoto Ito (Department of Pure and Applied Physics, Kansai University)

anpc2021-MIto.mp4

11:15 → 11:30 Tea/Coffee/Short Break

11:30 → 13:30 Session 9: Nuclear Structure, Reactions and Dynamics

Convener: Alinka Lépine-Szily (USP)

11:30 Fission fragment spectroscopy of isotopically identified neutron rich nuclei

The single-particle excitations, particle-hole interactions, and mixing of various single particle configurations in nuclei with few valence particles or holes around $^{132}$Sn have been the subject of contemporary interest, both experimentally [1–4] and theoretically [5]. The excited states of these neutron-rich nuclei provide key inputs to understand the effective interactions in terms of large scale shell model calculations. Presence of high-j unique parity orbitals plays a major role in generating high spin states in these nuclei and is also responsible for occurrence of isomers in odd-A as well as in odd-odd nuclei in this region.

The neutron-rich nuclei with few valence particle / holes in Z=50, N=82 closed shell are only accessible via fission and direct identification of the nuclei with both mass (A) and charge (Z) selection is extremely challenging. Neutron-rich nuclei around $^{132}$Sn have been investigated using fission reaction of $^{238}$U beam of 6.2 Mev/u impinging on $^9$Be target at GANIL [6]. The isotopic identification (A, Z) of the fission fragments was obtained using the large acceptance magnetic spectrometer VAMOS++. The prompt $\gamma$ rays emitted from the recoiling fission products at the target position were detected using $\gamma$-ray tracking array AGATA and the EXOGAM segmented clover detectors were placed behind the focal plane of VAMOS++ to detect the delayed $\gamma$ rays. Some of the complimentary studies on low lying states have also been carried out from decay spectroscopy after $\alpha$ induced fission at VECC, Kolkata.

The high spin states of neutron rich Iodine nuclei above the long lived isomers are populated for the first time and new isomers are also identified from prompt-delayed spectroscopy [7]. The level structures are interpreted in terms of the systematics of odd-Z nuclei above the Z = 50 shell closure and large-scale shell model calculations.

References:
[1] A. Navin and M. Rejmund, in McGraw-Hill Yearbook of Science and Technology (McGraw-Hill, New York, 2014), p. 137.
[2] K. L. Jones et al., Nature (London) 465, 454 (2010).
[3] M. Rejmund et al., Phys. Lett. B 753, 86 (2016).
[4] S. Bhattacharyya et al., Phys. Rev. C 98, 044316 (2018).
[5] L. Coraggio, A. Covello, A. Gargano, and N. Itaco, Phys. Rev. C 87, 034309 (2013).
[6] Y. H. Kim et al., Eur. Phys. J. A 53, 162 (2017).
[7] R. Banik et al., Phys. Rev. C 102, 044329 (2020)

Speaker: Sarmishtha Bhattacharyya (Variable Energy Cyclotron centre)

Abstract_Sarmi_ANPC2021_Talk.pdf

12:00 A study of the nuclear structure in the even-even Yb isotopes

The medium-to-heavy mass ytterbium isotopes ($_{70}$Yb) in the rare-earth mass region are known to be well-deformed nuclei, which can be populated to very high spin. Spectroscopic information becomes scarcer as the neutron number increases, impeding the understanding of nuclear structure in this mass region, where interesting phenomena, such as shape coexistence, have been predicted. The lack of any experimental information on the structure of the neutron-rich $^{180}$Yb isotope and the lifetime of the $2_1^+$ state of $^{178}$Yb have greatly motivated this study inlaying the path for near-future experimental endeavors. In this work, energy levels, deformation parameters $\beta_2$, reduced transition probabilities $B(E2)$ and transition quadrupole moments $Q$ for even-even Yb isotopes have been calculated using a Phenomenological Model and the Interacting Boson Approximation 1. Additional results are presented using the following theoretical models: the Finite-Range Droplet Model, the Hartree-Fock BCS Model with MSk7 force, the Hartree-Fock-Bogoliubov Model with Gogny D1S force, the Relativistic Hartree Bogoliubov Model with the covariant energy density functional NL3$^∗$, the Hartree-Fock-Bogoliubov Model with UNEDF1, the Proxy SU(3) and the Pseudo SU(3) models. Also, numerical results for energy ratios for the Yb isotopes, with the Exactly Separable Davidson (ESD), Exactly Separable Morse, Exactly Separable Woods-Saxon, Deformation Dependent Mass Davidson (DDMD) and Deformation Dependent Mass Kratzer (DDMK) analytical solutions of the Bohr Hamiltonian have been obtained. Along these lines, the results for even-even $^{164-178}$Yb isotopes are compared to available experimental data, serving as benchmarks. An overall good agreement was found between available adopted data and theoretical predictions.

Speaker: Aikaterini Zyriliou (National and Kapodistrian University of Athens, Greece)

120-A_Zyriliou-A_study_of_the_nuclear_structure_in_the_even_even_Yb_isotopes.mp4

A. Zyriliou-Abstract.pdf

A. Zyriliou ANPC Presentation.pdf

12:20 Direct Measurement of Fusion Reaction in $^8$B + $^{40}$Ar using the Active-Target TexAT

V. Guimaraes $^{1)}$, J. C. Zamora $^{1)}$, G. V. Rogachev $^{2,3)}$, S. Ahn $^{2)}$, E. Aboud $^{2,3)}$, M. Assuncao $^{4)}$, M. Barbui $^{2)}$, J. Bishop $^{2,3)}$, A. Bosh $^{2,3)}$, J. Hooker $^{2,3)}$, C. Hunt $^{2,3)}$,
D. Jayatissa $^{2,3)}$, E. Koshchiy $^{2)}$, S. Lukyanov $^{5)}$, R O’Dwyer $^{2,3)}$, Y. Penionzhkevich $^{5)}$,B. T. Roeder $^{2)}$, A. Saastamoinen $^{2)}$, E. Uberseder $^{2)}$, and S. Upadhyayula $^{2,3)}$.

$^{1)}$ Instituto de Fisica, Universidade de Sao Paulo, SP, Brazil
$^{2)}$ Cyclotron Institute, Texas A&M University, College Station, TX, USA
$^{3)}$ Dep. of Physics and Astronomy, Texas A&M University, College Station, TX, USA
$^{4)}$ Universidade Federal de Sao Paulo, SP, Brazil
$^{5)}$ Flerov Laboratory of Nuclear Reactions, JINR, Dubna, Russia

The investigation of reaction mechanism involving weakly bound (stable and unstable) nuclei has been a subject of great interest in the last years. In particular, the low binding energy and strong cluster configuration in halo nuclei produces a decoupling between the valence particle and the core nucleus, which give rise to an increase of the breakup and/or transfer probability in the total reaction cross section [1,2]. It has been observed that the coupling of these direct processes affects the total fusion cross section producing a suppression at energies above the Coulomb barrier and an enhancement at sub-barrier energies, when compared with no-coupling one dimensional barrier penetration. Measurements of fusion cross section involving unstable nuclei are usually performed with indirect methods which most of the times are model dependent. For instance, fusion in $^{8}$B+$^{58}$Ni (below barrier) [3] and $^{8}$B+$^{28}$Si (above barrier) [4] were measured from evaporation yields of proton and alpha particles, respectively. Inconsistencies between these experimental results and predictions from coupled channel calculations are still not fully understood. To address these open questions, a direct fusion measurement for the $^{8}$B+$^{40}$Ar system at near Coulomb-barrier energies was performed at the Cyclotron Institute of the Texas A&M University using the active target TexAT (Texas Active Target) [5]. The present technique allowed a clear identification of fusion events from other reaction channels, as well as the evaporated charged particles, by reconstructing their tracks in the 3D space and energy deposited in the gas target. Results of this measurement will be presented and the comparison with the $^{8}$B+$^{58}$Ni and $^{8}$B+$^{28}$Si existing data will be discussed [6].

[1] L.F. Canto, V. Guimaraes, J. Lubian, M. S. Hussein, Eur. Phys. J. A 56, 281 (2020).
[2] L. F. C. P.R.S. Gomes, R. Donangelo and M.S. Hussein, Phys. Rep. 424, 1 (2006).
[3] E. F. Aguilera et al., Phys. Rev. Lett. 107, 092701 (2011).
[4] A. Pakou et al., Phys. Rev. C 87, 014619 (2013).
[5] E. Koshchiy, et al., Nuclear Inst. and Meth. A 957, 163398 (2020).
[6] J. C. Zamora, V. Guimaraes, et al., Phys. Lett. B 816, 136256 (2021).

Speaker: Valdir Guimaraes (Universidade de São Paulo - Brazil)

115-V_Guimaraes-8B_40Ar_Talk.mp4

12:40 Look for non-axially deformed halo nuclei

Halo phenomenon has long been a hot topic in nuclear physics. Due to the weakly binding nature, the Fermi surface of a halo nucleus is very close to the continuum threshold, and the pairing interaction can scatter nucleons from bound states to resonant ones in the continuum. It is therefore necessary to take into account the pairing correlations and continuum effects in describing the halo nuclei.

For spherical halo nuclei, the relativistic continuum Hartree-Bogoliubov (RCHB) theory interpreted microscopically the halo phenomenon in Li-11 and predicted the giant halo phenomena. For deformed halo nuclei, the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc), which takes into account the axial deformation degrees of freedom, pairing correlations, and continuum effects in a unified way, predicted the deformed halo nucleus Mg-44 and a shape decoupling between the core and the halo.

The non-axial shape, i.e., triaxiality, plays an essential role in understanding the nuclear chirality and wobbling. In order to explore the non-axially deformed halo nuclei, the triaxial relativistic Hartree-Bogoliubov theory in continuum (TRHBc) is developed, and the possible triaxially deformed halo nucleus Al-42 is investigated as an example.

Speaker: Kaiyuan Zhang (Peking University)

13:00 Novel method for accessing tens-to-hundreds femtoseconds nuclear state lifetimes, examples and results

I will presented a novel Monte Carlo technique based on DSAM (Doppler Shift Attenuation Method), which has been developed to determine lifetimes of excited states in the tens to-hundreds femtoseconds range in products of low-energy heavy-ion binary reactions [1]. These reaction processes are characterized by large energy dissipation, leading to complex velocity distributions which do not allow to apply standard Doppler broadened gamma-ray lineshape analysis. The technique is anticipated to be an important tool for lifetime investigations in exotic neutron-rich nuclei, produced with intense ISOL-type beams.

I will demontrate its relevance in connection with experiment, performed at GANIL with the AGATA+VAMOS+PARIS setup, to study neutron-rich O, C, N, nuclei. Excited states in this region, with known lifetimes, are used to validate the method between 20 fs to 400 fs lifetime range. Moreover extraction of the lifetimes of the second 2$^+$ states in $^{16}$C and $^{20}$O, which have beenpredicted to be in the hundred-femtoseconds time range and to strongly depend on the three-body term of the nuclear interaction will be presented [2].

References
[1] M. Ciemała, et al., Eur. Phys. J. A, 57:156, (2021)
[2] M. Ciemała, et al., Phys. Rev. C 101, 021303(R),(2020)

Speaker: Michał Ciemała (IFJ PAN Kraków, Polska)

13:30 → 14:00 Meal/Long Break

14:00 → 15:20 Session 10: Applied Nuclear Physics

Convener: Patrick Regan (University of Surrey &amp; The National Physical Laboratory, UK)

14:00 Advances in $^{211}$At production at Texas A&M University

Alpha emitting radionuclides with medically relevant half-lives are interesting for treatment of tumors and other diseases because they deposit large amounts of energy close to the location of the radioisotope. Researchers at the Cyclotron Institute at Texas A&M University are developing a program to produce $^{211}$At, an alpha emitter with a 7.2 h half-life. The properties of $^{211}$At make it a great candidate for targeted alpha therapy for cancer due to its short half-life and decay mechanism. Astatine-211 has now been produced multiple times and novel chemistry has been developed for the separation of the At from the Bi target. Innovations to improve the safety and reliability of this process have been enacted.

Speaker: Sherry Yennello (Texas A&M University)

14:30 DNA damage response of haematopoietic stem and progenitor cells to high-LET neutron irradiation.

The radiosensitivity of haematopoietic stem and progenitor cells (HSPCs) to neutron radiation remains largely underexplored, notwithstanding their role as target cells for radiation-induced leukemogenesis. This is important for radiation protection purposes, particularly for aviation, space missions, nuclear accidents and even particle therapy. In this study, HSPCs (CD34+ cells) were isolated from umbilical cord blood and irradiated with 60Co γ-rays (photons) and high energy p(66)/Be(40) neutrons. A significant higher number of DNA DSBs was observed after 0.5 Gy neutrons of 1.277±0.118 foci/cell compared to 0.839±0.141 foci/cell for photons at 2 hours, but decreased to similar levels for both radiation qualities after 18 hours. However, differences in late apoptosis were observed between photons and neutron at 18 hours, 43.17±6.10 % versus 55.55±4.87 % respectively. A significant increase in cytogenetic damage was observed after both 0.5 and 1 Gy neutron irradiation compared to photons. No difference in nuclear division index was observed between both radiation qualities. The results point towards a higher induction of DNA damage after neutron irradiation in HSPCs followed by a fast error-prone DNA repair, which contributes to genomic instability and a higher risk of leukemogenesis.

Speaker: Monique Engelbrecht (NRF-iThemba LABS)

14:50 Production and chelation of alpha-emitting radiometals for targeted alpha therapy (TAT)

Coupling alpha-emitting radionuclides with disease seeking targeting vectors for site-selective delivery of cytotoxic radiation has the potential to be a powerful technique for treating metastatic and hard to treat cancers. The success of this type of treatment, termed targeted alpha therapy (TAT), is reliant on the availability of isotope and ability to securely tether said isotope to a biomolecule of interest. With four alpha particles in its decay chain, actinium-225 (²²⁵Ac; t_1/2 = 9.9 d) is a promising candidate isotope for TAT. Similarly, the single alpha-emitter lead-212 (²¹²Pb; t_1/2 = 10.6 h) has generated significant interest as a matched theranostic pair with ²⁰³Pb (t_1/2 = 51.9 h), compatible with single-photon emission computed tomography (SPECT) imaging. The current limited global supply, and lack of appropriate chelating ligands (molecules used to bind the isotope to the biomolecule) has delayed the advancement of TAT-drugs towards the clinic.¹ Herein, we describe efforts to produce, purify, and evaluate the radiolabeling ability of ²²⁵Ac and ²¹²Pb, by leveraging TRIUMF’s unique infrastructure (located in Vancouver, Canada). For ²²⁵Ac, the ISAC isotope separation on-line (ISOL) facility, as well as the 500 MeV cyclotron were used to produce preclinical and clinical amounts of isotope, respectively. For ²¹²Pb, a ²²⁸Th generator was manufactured.
²²⁵Ac alongside parent nuclide radium-225 (²²⁵Ra; t_1/2 = 14.8 d) were produced via spallation of uranium carbide targets with 480 MeV protons on ISOL’s radioactive beam facility. Downstream from the target, a high-resolution mass separator was used to isolate ²²⁵Ra and 225Ac ions from other isotopes produced in the spallation process. Implantation resulted in isolation of 1.0 – 7.5 and 1.4 – 18.0 MBq of ²²⁵Ra and ²²⁵Ac, respectively. The implanted activity was etched off the sample stage with dilute acid, and ²²⁵Ac was separated in >99% yield from ²²⁵Ra using solid phase extraction (DGA resin).² This method has resulted in the isolation of MBq quantities of both ²²⁵Ra and ²²⁵Ac, where the former can be stored and used as a generator for 225Ac. Clinical scale-production via irradiation of 232Th targets on the 500 MeV cyclotron resulted in ²²⁵Ac products suitable for our studies. Conveniently, the by-products produced during spallation can be extracted to prepare a ²²⁸Th/²¹²Pb generator that can deliver up to 9 – 10 MBq of ²¹²Pb daily.³ Subsequently, ²²⁵Ac and ²¹²Pb coordination properties with a library of chelating ligands along with commercial standard DOTA were evaluated by testing radiolabeling efficiency, and complex stability.
In conclusion, we have successfully established a production method for ²²⁵Ac which yields activities adequate for pre-clinical screening (²²⁵Ac via ISOL, or ²¹²Pb via ²³²Th spallation) or clinical production (²²⁵Ac via ²³²Th spallation). Furthermore, several novel radiometal-chelators showed promising radiolabeling properties and kinetic inertness in vitro compared to commercial standards and will be tested in vivo in future studies.

(1) Robertson, A. K. H. et al. Curr. Radiopharm. 2018, 11 (3), 156–172. https://doi.org/10.2174/1874471011666180416161908.
(2) Ramogida, C. F.; et al. EJNMMI Radiopharm. Chem. 2019, 4 (1), 21. https://doi.org/10.1186/s41181-019-0072-5.
(3) McNeil, B. L.; et al. EJNMMI Radiopharm. Chem. 2021, 6 (1), 6. https://doi.org/10.1186/s41181-021-00121-4.

Speaker: Caterina Ramogida (Simon Fraser University & TRIUMF)

15:20 → 15:30 All Delegates Move Over to Poster Session - Gather.Town

15:30 → 17:30 Poster Session 2: Mixed Topics

Sponsored by School of Physics, University of the Witwatersrand

15:30 A ground-based evaluation of the impact of neutron dose rate on health effects during space travel

The lack of information on how biological systems respond to low-dose and low dose-rate radiation makes it difficult to accurately assess the corresponding health risks. This is of critical importance to space radiation, which remains a serious concern for long-term manned space exploration. Therefore, a growing number of particle accelerator facilities implement ground-based analogues to study the biological effects of simulated space radiation. In this presentation, we will introduce first results of a project on the “Optimization and validation of a unique ground-based in vitro model to study space health effects” (INVEST) at iThemba LABS, which aims to implement a first ground-based set-up to study space health effects in Africa. The focus of this work is on neutron irradiation, which is considered to be an important secondary component in space radiation fields. In a first set of experiments, the effect of neutron dose rate on immune system alterations and DNA double-strand break (DSB) induction and repair was investigated. Blood samples of adult volunteers were exposed to p(66)/Be(40) neutron irradiation (fluence-weighted average energy: 29.8 MeV) at a lower dose rate (LDR) of 0.015 Gy/min or a higher dose rate (HDR) of 0.400 Gy/min. DNA DSB formation was 40% higher at HDR exposure compared to LDR exposure. The DNA DSB levels decreased gradually to 1.65 ± 0.64 foci/cell (LDR) and 1.29 ± 0.45 (HDR) at 24 h post-irradiation, remaining significantly higher than background levels. The impact of neutron dose and dose rate on immune alterations was studied using the in vitro cytokine release assay. Recall antigens and mitogens were used to activate lymphocytes post-irradiation and dose rate effects on the cytokine production capacity of the cells were observed under specific conditions. The results give a first indication that the dose rate should be taken into account for health risk estimations related to neutron irradiation.

Speaker: Dr Randall Fisher (Division of Radiation Biophysics, Separated Sector Cyclotron Laboratory, NRF iThemba LABS)

231-R.Fisher-A ground-based evaluation of the impact of neutron dose rate on health effects during space travel.pdf

R Fisher Abstact_ANPC 2021.pdf

15:30 B(E2) value of even-even 124-130Barium transitional nuclei with cubic terms from Casimir invariant operators and IBM-1

Abstract
Several properties of nuclear structure for even- even 124-130Barium nuclei have been explored with Interacting Boson Model. This work studies the systematic reduced transition probabilities B(E2) ↓ of Ba isotopes with even neutrons from N=68 to 74. The values of parameters have been determined with the formation of cubic terms by Casimir invariant operators and addition of these terms by breaking O(6) symmetry of IBM Hamiltonian .We have studied systematically the transition rate R=B(E2: L+→(L-2)+ )/ B(E2: 2+→0+) of some of the low-lying quadrupole collective states in comparison with available experimental data. The results of this calculation are in good agreement with available experimental data. The even- even 124-130Barium isotopes show O(6) symmetry.
Keywords: B(E2), Interacting Boson Model, 124-130Barium isotopes

Speaker: Rekha Mehta Rekha (Guru Kashi University, talwandi sabo,punjab)

191-REKHA_MEHTA-B(E2) value of even-even 124-130Barium transitional nuclei with cubic terms from Casimir invariant operators and IBM-1.pdf

ABSTRACT2.docx

15:30 Charge changing cross section and proton distribution radii of Be isotopes

In this research, we tested a new idea to measure proton-distribution radii ($r_{\rm{p}}$) by heavy-ion secondary beam experiments. It is important for understanding the structures of nuclei to know the proton- and the neutron-distribution radii independently. From this point of view, we tried to develop a new method to deduce proton-distribution radii ($r_{\rm{p}}$) very efficiently using nuclear collisions .

Now, $r_{\rm{p}}$ can be measured by electron scattering and isotope shift measurements. They have high accuracy and precision, but applicable unstable nuclei are rather limited. On the other hand, the present new method could have the same degrees of accuracy and could measure a wide range of unstable nuclei.

The experiment was carried out at HIMAC, Heavy Ion Medical Accelerator in Chiba, in Japan. We measured charge changing cross sections ($\sigma_{\rm{cc}}$) for $^{7-12}$Be isotopes on proton, Be, C, and Al targets. Charge changing cross section ($\sigma_{\rm{cc}}$) is the cross section of changing the number of protons in the collision with the target nucleus. We can deduce charge changing cross sections ($\sigma_{\rm{cc}}$) from the number of incident particles $N_1$ and charge changed particles $N_2$:

\begin{equation}
\sigma_{\rm{cc}}=-\frac{1}{t}\rm{ln}\Bigl(1-\it{\frac{N_2}{N_1}}\Bigr)
\end{equation}

In the zeroth-order approximation, the cross section is approximated by equation (2).

\begin{equation}
\sigma_{\rm{cc}}=\pi(r_{\rm{T}}+r_{\rm{p}})^2
\end{equation}

![charge changing][1]

From eq (2), we can derive proton radii if target’s nucleon radius $r_{\rm{T}}$ and $\sigma_{\rm{cc}}$ are known. In practice, we need to use Glauber calculation with more realistic proton and neutron distributions both in the projectile and the target nuclei.

Moreover, when trying to link the charge changing cross-section and the proton distribution radius, the consideration of the proton evaporation process shown in fig. 2 is considered to be very important.
In this process, neutrons are firstly abraded, which excites prefragment and results in the evaporation of protons. If this process could be extracted independently, it would be very useful in deriving the proton-distribution radii from the charge changing cross sections.

![proton evaporation][2]

In the experiment, we used proton, Be, C, and Al targets. Proton target is particularly sensitive to neutrons in the projectile reflecting the isospin asymmetry of the nucleon-nucleon total cross sections, which amplifies neutron abrasion. In short, the proton-evaporation effect has large portion of the charge changing cross section on proton target $\sigma^{\rm{p}}_{cc}$.

So, we assumed that $\sigma^{\rm{p}}_{cc}$ multiplied by some value x: $x\sigma^{\rm{p}}_{cc}$ is the cross section of proton evaporation for Be, C, and Al targets. Therefore, adding $x\sigma^{\rm{p}}_{cc}$ to eq (2) would reproduce the experimental results of charge changing cross sections.

In practice, we introduced x for each target and a constant parameter Y as the first and second approximation terms:

\begin{equation}
\sigma_{cc} = \sigma_{\rm{Glauber}} +
x\Bigl(\sigma^{\rm{p}}{\rm{cc}}-[\sigma^{\rm{p}}{\rm{Glauber}}+Y]\Bigr)
\end{equation}

As a result, we figured out that only 4 parameters, x(for 3 targets) and Y could reproduce 15 data of charge changing cross section for Be isotopes very well. It suggests a possibility of this new method for the deduction of proton-distribution radii with high accuracy and efficiency applicable to a wide range of unstable nuclei.

![proton distribution radii][3]

Speaker: Gen Takayama

208_Gen-Charge changing cross section and proton distribution radii of Be isotopes.pdf

figure1_charge_changing.png

figure2_proton_evaporation.png

figure3_proton_distribution_radii.png

15:30 DURGA: A novel facility in India to study capture gamma, fission fragment and decay spectroscopy

The advent of high-efficiency $\gamma$ ray spectrometers with multiple types of detectors, digital signal processing-based data acquisition system, and the realistic possibility of taking a stride in the hitherto unknown territory of nuclear landscape are driving the low- and medium-energy nuclear physics into the path of exciting exploration. With this in consideration, a novel facility, DURGA (Dhruva Utilization in Research using Gamma Array), has recently been developed in Bhabha Atomic Research Centre, Mumbai, India. The concept and possible utilization of the aforesaid facility is very unique in the sense that it is the only facility in the country (India) for carrying out “prompt” $\gamma$-ray spectroscopic investigation using thermal neutron beam.
The facility consists of eight Compton-suppressed clover Germanium detectors and sixteen LaBr$_3$(Ce) fast scintillators. The heart of the DURGA facility is a multi-frequency digitizer-based trigger-less data acquisition system. The digital acquisition system has been tailor-made for the aforesaid array of eight Compton-suppressed Clover Ge detectors and sixteen LaBr$_3$(Ce) fast scintillators, with a provision of expansion in future. The system boasts of many novel features which will be discussed.
Low-spin, low-excitation energy regime has always been a fertile ground in γ ray spectroscopy to explore several exotic nuclear phenomena, such as, β and γ vibration, multi-phonon structures, and even octupole-hexadecapole deformation. The facility is planned to be heavily used in studying Capture Gamma prompt and decay Spectroscopy (CGS). Apart from basic research, such studies will contribute in direct and immediate determination of presence of certain elements/contaminants in a given material/substance (in small quantity) in a non-destructive manner.
Nuclei with higher neutron-to-proton ratios are difficult to study in accelerator-based facilities using stable projectile and target combinations. One of the means to access and study the structure/properties of such nuclei is nuclear fission. Thermal neutron induced fission fragment spectroscopy will provide access to these difficult-to-reach nuclei, and study their medium- and high-spin nuclear structures in detail. Additionally, decay spectroscopy of the neutron-rich fission fragment nuclei will reveal/affirm the decay chain of isotopes and low-spin structures of daughter nuclei. A few preliminary/test experiments have already been carried out using the facility. Details on these measurements will be presented during the conference.

Speaker: Dr Somsundar Mukhopadhyay (Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai, India)

15:30 Electron screening effect @ IJS

In nuclear reactions induced by low-energy charged particles, atomic electrons can participate in the process by screening the nuclear charge and so, effectively reduce the repulsive Coulomb barrier. Consequently, the measured cross section is enhanced by an effect called electron screening. In numerous experiments, different research groups [1-4] obtained extremely high values of electron screening, that are in several cases (depending on target-nuclei environment) more than an order of magnitude above the prediction based on available theoretical model [5].

Nevertheless, even as a considerable amount of experimental data was collected over the past twenty years, a suitable theory, which can give an explanation of this effect, has not yet been found. However, electron screening is very important in nuclear astrophysics. For nucleosynthesis calculations, precise reaction rates should be known at very low energies. At these energies charged-particle-induced reaction cross sections become difficult to measure due to their sharp drop with decreasing energy. Nowadays, the energies of astrophysical interest can only be reached in underground laboratories with high-current low energy accelerators [6]. In spite of that, even when the lowest energies are reached, the measurements do not give the nuclear cross section, since the reaction rate in the laboratory is always influenced by the atomic electrons that surround the reacting nuclei. This is a problem since we do not expect that the electron screening effect observed under laboratory conditions should be equal to the electron screening in stars.

Trying to understand this process, the effect of electron screening has been investigated by our group for already several years [7-9]. We measured the highest value of electron screening in a graphite target. The measured value is about a factor of 50 above the adiabatic limit prediction and much higher than any potential measured so far. Further, our results pointed out that the Z dependence of the screening is even higher than Z$ ^{2} $ instead of expected linear dependence. This rules out the theory based on static electron densities. In order to explain our data, we proposed a new model assuming that an electron is caught in the attractive potential of the two approaching nuclei, similar to the potential of the hydrogen molecular ion [8]. An overview of previous research works on this topic, same as our latest results will be presented.

[1] K. Czerski et al., Europhys. Lett. 68, 363 (2004)
[2] J. Kasagi et al., J. Phys. Soc. Jpn. 73, 608 (2004)
[3] F. Raiola et al., J. Phys. G 31, 1141 (2005)
[4] J. Cruz et al., Phys. Lett., B 624, 181 (2005)
[5] H. J. Assenbaum et al., Z. Phys. A: At. Nucl. 327, 461 (1987)
[6] C. Broggini et al., Ann. Rev. Nucl. Part. Sci. 60, 53 (2010)
[7] J. Vesić et al., Eur. Phys. J. A 50, 153 (2014)
[8] A. Cvetinović et al., Phys. Rev. C 92, 065801 (2015)
[9] M. Lipoglavšek et al., Phys. Lett. B 773, 553 (2017)

Speaker: Aleksandra Cvetinović (JSI)

15:30 Emerging collectivity in neutron-hole transitions near doubly magic 208Pb

Nuclei around doubly magic $^{208}$Pb have long served as a testing ground for the validity of the shell model. While the high-spin states of these nuclei have been studied extensively, data on electromagnetic transition rates between the low-spin states are scarce. Members of the $N = 125$ isotone chain – including $^{209}$Po, $^{211}$Rn and $^{213}$Ra – exhibit a ground state with spin-parity of $J^{\pi} = 1/2^-$, and a $5/2^-$ first-excited state at near-constant excitation energy. The ground state can be attributed to a p$_{1/2}$ neutron hole coupling to the $0^+$ ground-state of the neighbouring semi-magic, $N = 126$ core; likewise, coupling the ground state of the core to a $\nu f_{5/2}$ hole accounts for the excited $5/2^-$ state.

These nuclei have been studied using stable-beam experiments at the Australian National University Heavy Ion Accelerator Facility. Lifetimes of the $5/2-$ states in the $N = 125$ isotone chain were measured directly from γ- γ time differences using Compton-suppressed, ultrafast LaBr$_3$ scintillators installed in the CAESAR detector array. The near-constant excitation energy of the $5/2^-$ state across the chain suggests that the simple single-hole structure persists as pairs of protons are added. However, the measured $B(E2; 5/2^- \to 1/2^-$) values indicate enhanced collective contributions from valence protons that increase with Z. It appears that the near-constant $5/2^-$ excitation energies are a coincidental outcome of the interplay between the single-particle behaviour and emerging collectivity beyond the shell-model valence space. Shell-model calculations were performed to understand the microscopic origins of this behaviour.

This research was supported by the Australian Research Council through grant numbers No.~DP170101673 and No.~DP170101675, and by the International Technology Center Pacific (ITC-PAC) under Contract No.~FA520919PA138. A.~A., B.~J.~C., J.~T.~H.~D., T.~J.~G., and B.~P.~M. acknowledge the support of the Australian Government Research Training Program. Support for the ANU Heavy Ion Accelerator Facility operations through the Australian National Collaborative Research Infrastructure Strategy (NCRIS) program is also acknowledged.

Speaker: Dr Matthew Gerathy (The Australian National University)

197-MSM_Gerathy-Emerging_collectivity_in_neutron-hole_transitions_near_doubly_magic_208Pb.pdf

15:30 Erosion of N = 28 Shell Closure in Light Nuclei

The development of deformation in proton deficient N = 28 isotones is analyzed by employing relativistic Hartree-Bogoliubov (RHB) model based on recently introduced energy density functional DD-PCX. The calculations are performed by imposing constraints on axial and triaxial mass quadrupole moments. The regions of low-level density in neutron and proton single-particle states, around the Fermi level, favor the onset of deformation and shape coexistence. The relativistic functional DD-PCX provides a good description of the reduction of N = 28 spherical shell gap, the evolution of shapes, and disappearance of N = 28 shell closure, that occur due to quadrupole excitations across it. The results are compared with previous studies based either on the mean-field approach or the shell-model approach.

Speaker: Mr Pankaj Kumar (Himachal Pradesh University, Shimla)

236-Pankaj_Kumar-Erosion_of_N=28_Shell_Closure_in_Light_Nuclei_Poster.pdf

Absract.pdf

15:30 Fast timing characteristics of 1.5′′ x 1.5′′ CeBr$_{3}$ detector

Measurement of lifetime of nuclear excited states and extraction of electromagnetic transition strengths from that provides direct insight into nuclear structure. Gamma ray coincidence spectroscopy with new-age fast scintillator detectors, such as, LaBr$_{3}$(Ce) and CeBr$_{3}$ serves as a useful tool for lifetime measurements in sub-nanosecond ranges. Although the energy resolution of CeBr$_{3}$ is slightly poorer than that of LaBr$_{3}$(Ce), but with comparable time resolution and without any internal activity, CeBr$_{3}$ scintillator detectors emerge as a potential alternative to LaBr$_{3}$(Ce).
At Variable Energy Cyclotron Centre (VECC), Kolkata, 1.5′′ x 1.5′′ CeBr$_{3}$detectors coupled with a new Photo-Multiplier tube Hamamatsu R13089-100 has been characterized. An energy resolution of 4.1% has been obtained at 662 keV of $^{137}$Cs source. Absolute photo-peak efficiencies at different source-to-detector distances have been measured [1]. GEANT4 simulation has been carried out which reproduces pulse height spectra and absolute efficiencies reasonably well. The best time resolution (TAC FWHM) of 199(2) ps between two CeBr$_{3}$detectors for 1173-1332 energy cascade of $^{60}$Co source and 327(3) ps for 511-511 keV of $^{22}$Na source have been obtained after optimizing various parameters. With the knowledge of basic characteristics of two detector set-up, time-walk response for this set-up was determined using Mirror Symmetric Centroid Difference (MSCD) method [2]. $^{152}$Eu source has been used to calibrate Prompt Response Difference[PRD(E$_{\gamma}$)] curve for different high voltages at various CFD delays [3]. For each set-up, known lifetimes of two states of $^{133}$Cs - (3/2)$^{+}$state at 384 keV and (5/2)$^{+}$state at 161 keV, populated via electron capture decay of $^{133}$Ba, have been reproduced.
Nuclei near $^{208}$Pb region are expected to have spherical structure at lower spin and collective structure at higher spin and excitation energies. For even-even Po (Z=84) isotopes in this region, the variation of R$_{4/2}$ ratio approaches towards vibrational limit as neutron holes increase whereas, E2 transition strength increase from $^{210}$Po to $^{206}$Po [4]. The low-lying states of neighboring odd-A nuclei in this region are mainly described by the coupling of one neutron hole with the nearest even-even core. The lifetime measurement of low-lying states of Po isotopes will be of great importance to understand the interplay between single particle and collective structure. Lifetime of (11/2)$^{-}$state at 1521.85 keV of $^{209}$Po has been determined. The excited states of $^{209}$Po were populated via electron capture decay of $^{209}$At which was produced using the reaction $^{209}$Bi ($\alpha$, 4n) $^{209}$At at 52 MeV beam energy at VECC, kolkata. The value obtained has been found to be in good agreement with the previously reported value [5].
References:
[1] S.Das, et al., Proc. of DAE-BRNS Symp. on Nucl. Phys.70 (2019) 986
[2] J.-M.Regis, et al., NIM A 622 (2010) 83-92
[3] J.-M.Regis, et al., NIM A 684 (2012) 36-45
[4] M. Stoyanova, et al., PRC 100, 064304 (2019)
[5] V. Karayonchev, et al., PRC 103, 044309 (2021)

Speaker: Sneha Das

170-S_Das-Fast timing characteristics of 1.5″x1.5″ CeBr3 detector.pdf

ANPC_abstract_Sneha_VECC.pdf

15:30 FRAISE: The New Fragment In-Flight Separator at INFN-LNS

The study of exotic nuclei is presently a challenge for nuclear physics. Indeed, exotic nuclei properties are useful to investigate nuclear structure models, features of the nuclear force and nuclear reactions important for nuclear astrophysics. These investigations can be helpful also to add a further constraint to the knowledge of the Equation of State of nuclear matter. Within this framework, various facilities have been developed worldwide with the aim to deliver Radioactive Ion Beams (RIBs) [1]. In the last 15 years, at Laboratori Nazionali del Sud of INFN (INFN-LNS) RIBs have been produced through the In-Flight Fragmentation method, using the in Flight Radioactive Ion Beams at LNS (FRIBs@LNS) facility [1-3]. Presently, the ongoing project of the LNS (POTLNS), based on an upgrade of the Superconducting Cyclotron, aims to deliver light and medium masses nuclei with a power up to ≈ 10 kW. This project has brought a new perspective also for the production of RIBs. Indeed, the building of a new fragment separator, named FraISe (Fragment In-flight Separator), is underway to exploit primary beams with power of 2-3 kW for the production of high-intensity RIBs [1-3]. We report the status and the perspectives of the FraISe facility. Moreover, R&D studies for new diagnostics and tagging devices will be also discussed.

[1] Russotto P. et al., Jour. of Phys. Conf. Ser., 1014 (2018) 012016 and references therein.
[2] Russo A.D. et al., NIM B, 463 (2020) 418.
[3] Martorana N.S., Il Nuovo Cimento 44 C (2021) 1.

Speaker: Dr Nunzia Simona Martorana (Dipartimento di Fisica e Astronomia and INFN-LNS)

Abstract 221_NS_MARTORANA_FRAISE THE NEW FRAGMENT IN-FLIGHT SEPARATOR AT INFN.pdf

Abstract-Martorana.pdf

15:30 Measurement of 17F breakup on 4He using the pAT-TPC

17F is a well-known proton halo nucleus (Sp = 0.6 MeV) that can be described as a 16O core nucleus plus a weakly bounded proton. The 17F breakup mechanism can be induced by electromagnetic and nuclear interactions. Previous experiments of 17F breakup on 58Ni and 208Pb nuclei show a strong interference of Coulomb and nuclear breakup processes. New experimental data of 17F breakup on a 4He target were measured using the prototype Active Target-Time Projection Chamber (pAT-TPC). The pAT-TPC is a detector that uses a gas volume as both target and tracking medium, covering almost a 4pi solid angle. The detector system allows a particle tracking from where it is possible to extract the scattering angles and the reaction vertex with good precision. Preliminary results of exclusive and inclusive breakup will be discussed in this talk.

Speaker: Guilherme Ferrari Fortino (Instituto de Física da USP)

Poster_Congresso.pdf

15:30 Multi-channel experimental and theoretical approach to the $^{12}$C($^{18}$O,$^{18}$F)$^{12}$B single charge exchange reaction at 275 MeV

In recent years, the search for neutrinoless double beta ($0\nu\beta\beta$) decay has attracted much interest among physicists due to the extraordinary consequences that could derive from its observation. The NUMEN project aims to provide experimental information on the nuclear matrix elements involved in the expression of $0\nu\beta\beta$ decay half-life by measuring the cross section of nuclear double charge exchange reactions. In this framework a full understanding of the reaction mechanisms involved in double and single charge exchange nuclear reactions is mandatory for the purposes of the NUMEN project.

An interesting case study, to test the capabilities of state-of-art nuclear reaction and nuclear structure theories, is the net of nuclear reactions involved in the $^{18}$O + $^{12}$C collision at 275 MeV incident energy. The experiment has been performed at the INFN-LNS and the experimental results and the theoretical analysis for the single charge exchange, elastic and inelastic scattering, one-neutron addition and one-proton removal nuclear reactions will be discussed during the communication.

The experimental and theoretical study of the $^{12}$C($^{18}$O, $^{18}$O)$^{12}$C elastic and inelastic scattering was performed to access the initial state interaction (ISI) responsible for the distortion of the many-body wave functions of the incoming nuclei. In addition to the ISI and the many-body properties of the nuclear wave functions involved in the studied reactions, the most crucial and debated aspect in the SCE nuclear reactions is the competition between the direct process, proceeding via the deeply studied meson-exchange and the sequential neutron-proton or proton-neutron transfer processes. In this framework, also the $^{12}$C($^{18}$O,$^{19}$F)$^{11}$B one-proton knock-out and the $^{12}$C($^{18}$O,$^{17}$O)$^{13}$C one-neutron pick-up reaction channels have been analysed to constraint the single particle components of the many-body nuclear wave functions of the involved nuclei.

The goal of this work is to produce and to theoretically analyse the experimental data using state-of-art nuclear structure and reaction theories in a unique comprehensive and coherent theoretical calculation. The holistic approach, applied both to the experimental and the theoretical analysis, is the main feature and novelty of the work presented here and justifies the interest of the NUMEN collaboration.

Speaker: Alessandro Spatafora (INFN-LNS)

223-A_Spatafora-Multi-channel study of the 12(18O,18F)12B single charge exchange reaction at 275 MeV.pdf

15:30 Novel Receptor Tyrosine Kinase Pathway Inhibitors for Targeted Radionuclide Therapy of Glioblastoma

Glioblastoma (GB) remains the most fatal brain tumor with a median survival of approximately 14 months and less than 10% of patients living longer than 5 years from diagnosis. GB tumors are characterized by a high infiltration rate and treatment resistance. At recurrence, there is no consensus on the standard of care as no therapeutic options thus far could demonstrate a substantial survival benefit. An improved understanding of the underlying disease pathology and the causes for these treatment challenges might aid the development of new GB therapy strategies. One particular strategy is the development of theranostic agents that combine diagnostic molecular imaging with therapy using the same agent. The theranostic agent thereby investigates the presence of a certain target on the tumor cells of the patient while the therapeutic version of the agent (commonly a radioactive derivative) binds to the same target and induces tumor cell death by emitting radiation, while sparing healthy normal tissues. The latter approach is called targeted radionuclide therapy (TRT).
Mutations in receptor tyrosine kinases (RTKs) and aberrant activation of their intracellular signaling pathways have been linked to malignant transformation and therapy resistance and have driven the development of a new generation of drugs that block or attenuate RTK activity. Overexpression and/or mutation of RTKs is common in GB, and therefore receptor tyrosine kinase inhibitors (RTKIs) have been investigated to improve the dismal prognosis of GB in an effort to evolve into a personalized targeted therapy strategy. RTKIs consist of mainly two categories, monoclonal antibody-based drugs that bind to the extracellular domain of the receptor and small molecule inhibitors acting intracellularly, both of which result in blocking the downstream signal trans-duction cascade. Numerous RTKIs have been approved in the clinic and several radiopharmaceuticals are part of (pre)clinical trials as a non-invasive method to identify patients who could benefit from RTKI. The latter opens up the scope for theranostic applications.
In this work, recently published in MDPI Pharmaceuticals, the option to use the tyrosine kinase pathway as a target for GB radiopharmaceutical development, and specifically for TRT, was explored. The focus was on seven tyrosine kinase receptors, based on their central role in GB: EGFR, VEGFR, MET, PDGFR, FGFR, Eph receptor and IGF1R. Finally, by way of analyzing structural and physiological characteristics of the RTKIs with promising clinical trial results, four small molecule RTKIs were selected based on their potential to become new therapeutic GB radiopharmaceuticals.

Speaker: Julie Bolcaen (Radiobiology, Radiation Biophysics Division, Nuclear Medicine Department, iThemba LABS, Cape Town 7131, South Africa)

230-JB_Bolcaen-Novel Receptor Tyrosine Kinase Pathway Inhibitors for Targeted Radionuclide Therapy of Glioblastoma.pdf.pdf

Graphical abstract.png

15:30 One neutron removal cross sections for the 16N isomeric state

The enhancement of halo neutron removal cross sections in neutron halo nuclei is well known and is one of the evidences for the neutron halo structure. We have measured neutron removal cross sections for several exotic light nuclei to reveal their characteristic neutron-halo-like structures.(M.Fukuda et al, Phys. Lett. B 268, (1991), 339-344)
　The difference in the nuclear structure between the ground and the isomeric state of $^{16}\mathrm{N}$ can be explained by the orbitals in which the valence neutron is sitting. Considering the spin and parity, the valence neutron is considered to be mainly occupying in the $1\mathrm{d}_{5/2}$ orbital in the ground state and in the $2\mathrm{s}_{1/2}$ orbital in the isomeric state. Therefore, the valence neutron in the $^{16}\mathrm{N}$ isomeric state, with effects of $2\mathrm{s}_{1/2}$ orbital and its relatively small neutron-separation energy of 2 MeV, can be distributed more broadly in the radial direction. Attachment [1] shows the calculated nucleon density distributions of $^{16}\mathrm{N}$ valence neutrons using the single-particle model. The spread of the density distribution depends on which orbital the valence neutron resides in. Therefore, the $^{16}\mathrm{N}$ isomeric state is a candidate for neutron halo nucleus. The halo nucleus in the excited state has not been observed directly with experimental evidences.
　The results of this research can also contribute to astrophysics. One of the nucleosynthesis processes is nuclear reactions in stars. The highest temperature among stars is about 1GK, which corresponds to about 100 keV in energy. This is the same order of magnitude as the excitation energy of $^{16}\mathrm{N}$ isomer(120 keV). This suggests that $^{16}\mathrm{N}$ isomer is existing in stars with a certain probability and may contribute significantly to the synthesis of elements. Therefore, the study of nuclear structure of $^{16}\mathrm{N}$ isomer will be useful for elucidating the mechanism of nucleosynthesis.
In the present study, we measured one neutron removal cross sections using secondary beams of $^{16}\mathrm{N}$ with a mixture of ground and isomeric states. We used two types of primary beams, $^{15}\mathrm{N}$ and $^{18}\mathrm{O}$, to produce $^{16}\mathrm{N}$ beams with different isomeric ratios, and compared the one neutron removal cross sections measured with each secondary beam. The experiments were carried out at the HIMAC heavy-ion synchrotron facility at National Institute for Radiological Sciences(NIRS), Japan.
　The experimental results show that the neutron removal cross section obtained from a $^{16}\mathrm{N}$ beam with a large isomeric ratio, which was produced from $^{18}\mathrm{O}$, is large compared to that obtained with a $^{16}\mathrm{N}$ beam with a small isomeric ratio produced from $^{15}\mathrm{N}$. This result suggests that the $^{16}\mathrm{N}$ isomeric state is considered to have a neutron-halo-like structure.

Speaker: Miki Fukutome

ANPC2021ポスター.pdf

15:30 Recent results from INGA and VENUS at VECC

The Indian National Gamma Array (INGA), which moves between the three major accelerator centres in India, was recently setup at VECC, Kolkata. Moreover, a complementary horizontal array of clover detector, VENUS (VECC Nuclear Spectroscopy) array was also setup. Several experiments have been performed to study the medium and high spin states in nuclei with these two array using light ion (proton and alpha) as well as heavy-ion beams from the K-130 cyclotron at VECC. Though it has limitation to produce very high spin states, but the alpha beam has certain advantages on the study of nuclear structure. Among the nuclei studied, interesting results have been obtained for the heavy nuclei just below the $Z = 82$ shell closure, the structure of which are severely affected by presence of the intruder high-j proton and neutron orbitals. Extending our study on Tl nuclei, we have identified a transition from chirality in $^{194}$Tl [1] to magnetic rotation in $^{195}$Tl [2]. In the odd-proton nucleus, $^{183}$Au, we have strong evidence of wobbling motion based on two high-j configurations, $h_{9/2}$ and $i_{13/2}$ [3]. The contrasting nature of the variation of the wobbling energies with spin in these two transverse wobbling bands were interpreted with a generalised picture of Frauendorf-Donau model [4]. Evidence of gamma vibration band and unfavoured long-axis rotation have been identified in the odd-neutron nucleus $^{187}$Os [5]. The details of the experiments, results and interpretations will be presented in the conference.

References:
[1] T. Roy et al., Phys. Lett. B782, 768 (2018).
[2] S. Nandi et al., Phys. Rev. C 99, 054312 (2019)
[3] S. Nandi et al., Phys. Rev. Lett. 125, 132501 (2020).
[4] S. Frauedorf and F. Donau, Phys. Rev. C 89, 014322 (2014).
[5] S. Nandi et al., in review (2021)

Speaker: Gopal Mukherjee (Variable Energy Cyclotron Centre, Kolkata, India)

200-G_Mukherjee-Recent_Results_From_INGA_And_VENUS_AT_VECC.pdf

15:30 Recent tests on the construction of a new correlator for neutrons and charged particles

With the advent of new facilities for radioactive ion beams mainly rich in neutrons, SPES @ LNL, FRAISE @ LNS and FAIR @ GSI to give some examples, the detection of neutrons and charged particles in Heavy radioactive Ion collisions with both high angular and energy resolutions became a mandatory request. As a consequence, the construction of new multi-detection systems suitable for correlations studies between neutrons and charged particles became an important perspective.
The contribution will illustrate the results of recent tests performed on new plastic material, the EJ276 both in the "green-shifted" and in the ordinary versions, coupled with Photon Multiplier Tubes (PMTs) or Silicon based-PM (SiPM) fast device. These experimental works are aimed at designing an advanced high efficiency neutron and charged particles prototype of a multi-element detector with both high energy and angular resolution.

Speaker: Emanuele Vincenzo Pagano (INFN - LNS)

201_EV_PAGANO_Recent tests on the construction of a new correlator for neutrons and charged particles_pdf.pdf

Abstract_ANPC2021_EVP_new_pdf.pdf

15:30 Resonances in 11C above 10B+p threshold using thick target in inverse kinematics

The resonance structure in 11C is important to understand 7Be(α,γ)11C reaction in the pp-chain of Sun and for the 10B(p,α)7Be reaction as the contamination of the candidate of aneutronic fusion reaction 11B(p,2α) 4 He. Above the proton threshold, there are discrepancies in the excitation energies and lack of spin-assignment for the resonances in 11C nucleus. For this, an elastic scattering experiment of 10B+p was conducted and the R-matrix calculations are performed for the inverse kinematics data using the code Azure2 [1]. The resonant parameters such as the energy, spin-parity Jπ , and the proton-decay partial width are extracted and a comparison is performed with the results obtained from direct kinematic data [2]. Prior to this, similar calculations were performed for the reaction 12C+p [3,4] where the resonance structure is well established.
References:
[1] R. E. Azuma, E. Uberseder, E. C. Simpson, C. R. Brune, H. Costantini, R. J. de Boer, J. Görres, M. Heil, P. J. LeBlanc, C. Ugalde, and M. Wiescher. Phys. Rev. C 81, 045805 (2010).
[2] M. Chiari, L. Giuntini, P. Mandò, and N. Taccetti, Nucl. Instrum. Methods Phys. Res., Sect. B 184, 309 (2001).
[3] S. Sambi et al., Eur. Phys. J. A 51 (2015).
[4] H.O. Meyer, G.R. Plattner, I. Sick, Z. Phys. A 279, 41 (1976).

Speaker: Gurpreet Kaur

207-G_Kaur-Resonances in 11C above 10B+p threshold using thick target in inverse kinematics.pdf

Abstract_ANPC2021.pdf

15:30 Rotational Structure in Nuclei Near 66Fe

Studies of the "heavy" island of inversion near the N=40 isotones between Ca and Ni have, to date, focused on determining the degree of collectivity in even-even nuclei using properties of 2+ transitions. While collective rotational structures are understood to be present, limited results are available to characterize these structures. In this work, we report on the results from an experiment conducted at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU) using a secondary fragmentation reaction to populate higher angular momentum states. We discuss new transitions observed in 66Fe and odd-A neighbors, 67Co and 65Fe, and the interpretation of these level schemes in terms of the rotational model of the nucleus.

Speaker: Emma Rice

192-EG_Rice-Rotational_Structure_in_Nuclei_Near_66Fe.pdf

15:30 Selection rules of electromagnetic transitions for chirality-parity violation in atomic nuclei

Chirality is a subject of general interest in natural science. Nuclear chirality was first predicted in 1997 [1], and up to now more than 60 candidate chiral doublet bands in around 50 nuclei have been reported [2]. Based on the covariant density functional theory, a phenomenon named multiple chiral doublets (MχD), i.e., more than one pair of chiral doublet bands in one single nucleus, was predicted in 2006 [3], which has attracted extensive attentions.
In 2016, the MχD with octupole correlations were reported in 78Br [4]. This observation provides the first example of chiral geometry in octupole soft nuclei and indicates that the simultaneous breaking of chiral and reflection symmetries, i.e., Chirality-Parity (ChP) violation, may exist in nuclei. In the reflection-asymmetric triaxial nuclei, one expects to establish four nearly degenerate ∆I = 1ℏ bands, i.e., ChP quartet bands, experimentally, which stimulates further interests.
In this talk, I will briefly introduce the recently developed reflection-asymmetric triaxial particle rotor model (RAT-PRM) [5]. RAT-PRM provides a useful tool for the description of the ChP quartet bands. It is applied to investigate the ChP violation in atomic nuclei [6]. A new symmetry for an ideal ChP violation system is found and the corresponding selection rules of the electromagnetic transitions are derived. The fingerprints for the ChP violation including the nearly degenerate quartet bands and the selection rules of the electromagnetic transitions are provided.

[1] S. Frauendorf and J. Meng, Nucl. Phys. A 617 (1997) 131.
[2] B. W. Xiong and Y. Y. Wang, At. Data Nucl. Data Tables 125 (2019) 193.
[3] J. Meng, J. Peng, S. Q. Zhang, and S.-G. Zhou, Phys. Rev. C 73 (2006) 037303.
[4] C. Liu et al., Phys. Rev. Lett. 116 (2016) 112501.
[5] Y. Y. Wang, S. Q. Zhang, P. W. Zhao, and J. Meng, Phys. Lett. B 792 (2019) 454.
[6] Y. Y. Wang, X. H. Wu, S. Q. Zhang, P. W. Zhao, and J. Meng, Sci. Bull. 65 (2020) 2001.

Speaker: Dr Yuanyuan Wang (North China Electric Power University)

145_Yuanyuan_WANG_Selcetion rules of EM transitions for ChP violation in atomic nuclei_Poster .pdf

15:30 Shape Coexistence and Octupole Correlations in 72Se

Atomic nuclei are unique quantum-body systems where the spontaneous symmetry breaking phenomena enrich a variety of shapes and structures. In recent years, the nuclei lying in the vicinity of the mid-shell region have attracted considerable attention as it exhibits a class of remarkable phenomena such as shape coexistence, shape evolution, octupole correlations, chirality, etc. The advancements in the detection technology with high resolution detector arrays like Indian National Gamma Array(INGA) [1], AGATA etc, have revolutionised the experimental scope of studying nuclear strucuture on the basis of such exotic phenomena. In the present work, high-spin excited states of 72Se nucleus have been populated using 50Cr(28Si, α2p)72Se fusion evaporation reaction at a beam energy of 90 MeV. The de-exciting γ-rays were detected using the Indian National Gamma Array (INGA) at IUAC, New Delhi. The well-determined shape coexistence feature of 72Se isotope has been further studied using the RDCO-Polarization method which was conveniently used to determine the M1/E2 character of ∆I = 0, 454.5-keV transition. Additionally, 72Se isotope having Z = 34, lies in the octupole coupling region of the single particle level orbitals. The first observation of enhanced E1 transitions, in A ≈ 70 mass region, decaying from the levels in the lowest negative parity band to first excited 0+2 band has been reported in this study. The energy separation parameter [∆E(I)] and frequency ratio between positive and negative parity bands further supports the observation of such reflection asymmetric structure. The experimental observations are also interpreted in terms of cranked Nilsson-Strutinsky model and total Routhian surface calculations, providing evidence of shape coexistence.

REFERENCES
[1] S. Muralithar et al., Nucl. Instrum. Methods Phys. Res.Sect. A 622, 281 (2010).

Speaker: Arunita Mukherjee (Guru Ghasidas Vishwavidyalaya, Bilaspur(C.G), India)

173_A_Mukherjee_Shape _coexistence_and_octupole_correlations_in_72Se.pdf

arunita_ancp2021.docx

15:30 Shapes, Softness and Non-Yrast Collectivity in 186W

The tungsten isotopes exist in a region of deformed nuclei with soft, triaxial shapes that evolve into oblate deformation as the proton, Z, and (or) neutron, N, numbers increase, before reaching sphericity at $Z = 82$ [1]. The heaviest stable W ($Z = 74$) isotope is at $A=186$. Its low-lying structure has been investigated in the past using Coulomb excitation [2] and $\beta$ decay [3]; however, experimental data on the non-yrast, higher-spin states are sparse due to their inaccessibility through any suitable heavy-ion fusion-evaporation reactions. In this work, non-yrast, excited states in neutron-rich $^{186}$W were populated via inelastic-scattering reactions using stable beams of $^{136}$Xe nuclei accelerated to 725 and 800 MeV (10 and 20% above the Coulomb barrier) [4]. Scattered ions were detected in CHICO2, and de-exciting γ rays in Gammasphere. Considerable progress was made in extending the $K^π = 2^+$ (γ), $K^π = 0^+$ and $K^π = 2^-$ (octupole) bands. A staggering pattern observed in the energies of levels in the $K^π = 2^+$ band was found to be consistent with a potential that gets softer to vibration in the γ degree of freedom with increasing spin. The odd-even staggering of states in the $K^π = 2^-$ band was found to exhibit a phase opposite to that seen in the γ band. This effect is most probably associated with Coriolis coupling to other, unobserved octupole vibrational bands in $^{186}$W.

This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Grants No.~DE-FG02-94ER40848 (UML), No.~DE-FG02-97ER41041 (UNC), No. DE-FG02-97ER41033 (TUNL) and DE-FG02-94-ER40834 (UMCP), and Contracts No.~DE-AC02-06CH11357 (ANL) and No.~DE-AC52-07NA27344 (LLNL), the International Technology Center Pacific (ITC-PAC) under Contract No.~FA520919PA138 (ANU), and the National Science Foundation. The research used resources of ANL's ATLAS facility, which is a DOE Office of Science user facility.

1. K. Kumar and M. Baranger, Nucl. Phys. A 110, 529 (1968).
2. F. K. McGowan $et~al$., Nucl. Phys. A 289, 253 (1977); W. T. Milner $et~al$., Nucl. Phys. A 177, 1 (1971); R. Kulessa, $et~al$., Phys. Lett. B 218, 421 (1989).
3. E. Monnand $et~al$., Nucl. Phys. A 134, 321 (1969).
4. V. S. Prasher, PhD thesis (2015).

Speaker: AJ Mitchell (Australian National University)

198-AJ_Mitchell-Shapes_softness_and_non_yrast_collectivity_in_186W.pdf

15:30 Structural Evolution and Octupole Correlations in Transitional Nuclei

The atomic nucleus is a fundamental and unique laboratory of nature for investigating the relationships among the fundamental symmetries. Exploring the relations between these symmetries is one of the major objectives of present-day researches. The nucleon-nucleon interactions inside the nucleus play a crucial role in the occurrence of various exotic phenomena like shape coexistence, γ-vibrational band, multi-phonon bands, back-bending, octupole vibration, octupole deformation, band termination, etc. Due to advancements in detection systems like high-resolution gamma detector arrays with large efficiency, it is now possible to study these exotic features exhibited by atomic nucleus. Recently, the high-spin states of the 73Br nucleus have been populated via the 50Cr(28Si, αp)73Br fusion evaporation reaction with a beam energy of 90 MeV. The deexciting gamma rays were detected using the Indian National Gamma Array (INGA) facility at Inter-University Accelerator Center (IUAC), New Delhi [1]. The half-life τ1/2 = 52(2) ns of isomeric 9/2+ state is determined using the intensity variation method. This lifetime is used to determine the magnitude of monopole transition strength ρ2(E0), which provides evidence for the shape coexistence at low spin states in odd mass 73Br nucleus. In addition, two new interconnecting enhanced E1 transitions between positive and negative parity yrast band have been added, which provides evidence for octupole correlation in ground state configuration. The lifetime of high spin states has also been measured using the Doppler-shift attenuation method (DSAM) for both positive and negative parity bands in 73Br nucleus. The observed transitional quadrupole moments decreases with increasing spin for these bands. The experimental observations have been interpreted in terms of the cranked Nilsson-Strutinsky model and total Routhian surface calculations, providing evidence for band termination at higher spin [2].

REFERENCES
[1] S. Muralithar et al., Nucl. Instrum. Methods Phys. Res.Sect. A 622, 281 (2010).
[2] S. Bhattacharya et al., Phys. Rev. C 100 014315 (2019).

Speaker: Mr Sutanu Bhattacharya (Guru Ghasidas Vishwavidyalaya )

172_S_Bhattacharya_Structural_Evolution_and_Octupole_Correlations_in_Transitional_Nuclei.pdf

itemba-abs.docx

15:30 Study of $^4$He + $^4$He inelastic scattering at the MAGNEX facility

A recent ab-initio calculation of the monopole transition form factor of $^4$He (Phys. Rev. Lett. 110, 042503 (2013)) pointed to a strong dependence on the different realistic potentials used. The inconsistencies met between the recent ab-initio form factor calculation and the existing data from $^4$He(e,e‘)$^4$He call for further investigation. In order to shed some light on this challenging subject, an exclusive measurement of the $^4$He + $^4$He $\rightarrow$ $^4$He + $^4$He $\rightarrow$ $^4$He + $^3$H + $^1$H reaction in the region of the first 0+ excited state of $^4$He was performed at the MAGNEX facility of INFN – Laboratori Nazionali del Sud. The $^4$He ions were momentum analyzed by the MAGNEX spectrometer, while the $^3$H ions were detected by the OSCAR telescope. The $^4$He + $^4$He $\rightarrow$ $^4$He + $^4$He* $\rightarrow$ $^4$He + $^3$He + n reaction was also measured simultaneously thanks to the large momentum acceptance of the MAGNEX spectrometer. The data analysis, including the relevant Monte Carlo simulations will be presented and discussed.

Speaker: Dr Vasileios Soukeras (Dipartimento di Fisica e Astronomia “Ettore Majorana”, Universit \`a di Catania, Catania, Italy and INFN – Laboratori Nazionali del Sud, Catania, Italy)

169-V_Soukeras_Study of 4He + 4He inelastic scattering at the MAGNEX facility.pdf

15:30 Study of electromagnetic properties of even-even medium-mass tellurium isotopes

The yrast spectra and electromagnetic properties of even-even medium mass tellurium isotopes are studied by employing projected shell model. From the analysis of projected shell model wave functions, the structure of yrast states is predicted. The low-lying yrast states up to spin 4+ are predicted to arise from zero-quasiparticle (qp) bands whereas the yrast 6+ states arise from 2-qp proton bands. The structure of yrast states changes further to 2-qp neutron bands as one moves along the yrast states. The B(E2) transition probabilities and g-factors are computed from projected shell model wave functions and compared with the available experimental data. The computed values are in agreement with the available experimental data. The electromagnetic quantities show a decrease in their values at spins wherever the structure of yrast states changes from 2-qp proton bands to 2-qp neutron bands. The present calculations predict spin 8+ states in lower mass tellurium isotopes to be of proton g7/2 character and spin 10+ states in higher mass tellurium isotopes to be of neutron h11/2 character.

Speaker: Rani Devi (University of Jammu)

195-Rani_Devi-Study_of _ electromagnetic_properties_of_even-even_medium-mass_tellurium_isotopes.pdf

15:30 Study of the reactions 78Kr+40Ca and 86Kr+48Ca at 10 AMeV

In this work, the principal results of data analysis of the reactions 78Kr +40 Ca and 86Kr +48Ca at laboratory energy of 10 AMeV, will be presented.
The experiment has been carried out at INFN-Laboratori Nazionali del Sud, with the 4π multidetector CHIMERA, which is used for the first time in this low energy regime, thanks to the implementation of its identification capabilities (pulse shape discrimination on silicon detectors).
The isospin influence on the reaction mechanisms in central and semi-central collisions has been investigated, with particular attention to Evaporation, and Fission-like processes following Fusion and to the break-up mechanism of the Projectile-like Fragment.
The dynamical or statistical nature of the mentioned reaction mechanisms has been studied through the analysis of fragments kinematics features and a dependence on the isopin of the involved system has been found.
The energy spectra of alpha particles have studied in order to obtain information about the temperature of their emission source in the two systems.
Finally, a comparison of the experimental data with the results of some theoretical models will be presented.

Speaker: Dr Brunilde Gnoffo (UNICT & INFN - CT)

poster_ANPC.pdf

15:30 Study of the single-nucleon transfer reactions in the $^{18}$O+$^{48}$Ti collision at 275 MeV

Single nucleon transfer reactions are considered among the best resources for probing single particle configurations in the populated many-body nuclear states. Besides a valuable spectroscopic tool, transfer reactions offer also an insight of the reaction dynamics. An example is the study of the degree of competition between sequential nucleon transfer and charge exchange reactions, the latter being of particular interest in the contest of single and double beta decay studies. Into this context, one-proton and one-neutron transfer reactions for the system $^{18}$O+$^{48}$Ti were measured at the energy of 275 MeV for the first time under the NUMEN and NURE experimental campaigns. The experiment was carried out at the MAGNEX facility of INFN-LNS in Catania. Angular distribution measurements for the reaction ejectiles were performed by using the MAGNEX large acceptance magnetic spectrometer. The data were analyzed by using two different reaction models aiming at validating the adopted reaction and nuclear structure inputs as well as to study the effect of inelastic excitations to the low-lying states of the projectile and target nuclei to the transfer cross-sections. The results of the analysis will be presented and discussed.

Speaker: Dr Onoufrios Sgouros (INFN-LNS)

175-O_Sgouros_Study of single-nucleon transfer reactions in the 18O+48Ti collision at 275 MeV.pdf

15:30 The B(E2) transition Probabilities for 122-130Te (Tellurium) Even-Even Isotopes with the help of Cubic terms from Casimir Invariant Operators and IBM-1

The interacting boson model-1 has been used to calculate the reduced electric transition probability B(E2) ↓ of even-even 122-130Te (Tellurium) isotopes with even neutrons from N = 70 to 78. The three-three boson interactions are also formed in the Hamiltonian from Casimir invariant operators. The parameters of best fit to measure the data is used from the experimental value of B (E2; 21+ → 01+) for even-even 122-130Te isotopes. The theoretical values are good in agreement especially with the experimental ones. The branching ratios B (E2; 41+ → 21+) / B (E2; 21+ → 01+) is less than 2 represents U (5) symmetry in 122-130Te isotopes.

Speaker: Pinky Rani (Research Scholar)

179_Pinky Rani_Physics_Poster.pdf

Abstract.docx

15:30 The design of a radon chamber for the calibration of radon monitors at the Centre for Applied Radiation Science and Technology, Mafikeng, South Africa.

The aim of the study was to design a radon chamber for the calibration of radon monitors at the Centre for Applied Radiation Science and Technology. There are radon monitors in South Africa, however, there are no known calibration facilities in the country. Therefore, there is a need to design radon chambers. The radon chamber was designed with a Perspex material of thickness 6mm and of volume of 0.5 m3 . Tudor-shaft soil samples whose 226Ra activities were known were used as radon sources. Experimentally; radon concentration, humidity, temperature and pressure were measured with the AlphaGUARDs. The computed radon ingrowth activities were used as a standard for calibrating the experimentally obtained radon activities from radon monitors (AlphaGUARDs). The calibration factors for the experiment were the differences between the radon monitors and the computed radon ingrowth activities at equilibrium determined as 223.97 Bq and 339.83 Bq.

Speaker: Moses Radebe

ABSTRACT MM RADEBE.pdf

Moses Radebe African Nuclear Physics Conference (ANPC).pdf

15:30 The energy levels of 21Ne and the s-process in rapidly rotating metal poor stars

Observations of Ultra Metal Poor stars such as HD 221170 [1] show that the abundances of elements heavier than silver can be reliably predicted by models of nucleosynthesis. However, elements between iron and silver have much higher observed abundances than predicted by models which only consider the ‘normal’ r- and s- processes. A potential solution for these underestimates is an extension of the s-process to rapidly rotating metal poor stars. Whether or not these stars contribute significantly to the abundances of the lighter heavy elements depends on several nuclear reactions; of specific interest is the ratio of 17O(α,n)20Ne to 17O(α,γ)21Ne [2]. This ratio is important as it determines the efficiency of the s-process in these stars. However, the cross section is too low to measure directly which means we must calculate the rate based on the parameters of the relevant states.

When calculating the rates of these reactions, the spin-parities of nuclear energy levels are important as rates of reaction depend upon them. Several states within the Gamow window in neon-21 have unknown spin-parities and this is a significant source of uncertainty in the model predictions [3]. In order to address this, an experiment in direct kinematics was conducted using the Enge split-pole spectrograph at the Triangle Universities Nuclear Laboratory (TUNL) [4]. A second experiment was later carried out in inverse kinematics at Argonne National Laboratory (ANL) using the HELIOS spectrometer. The aim of these experiments was to determine the unknown spin-parities relevant for nuclear astrophysics as well as constraining the neutron widths of the relevant states, via a study of the 21Ne(d,p) reaction; in both direct and inverse kinematics. The angular distribution for each state was determined and compared with Distorted-Wave Born Approximation predictions. The astrophysical motivation behind the experiment, results of the TUNL experiment and details of the ongoing analysis of data from HELIOS will be presented.

This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Contract Number DE-AC02-06CH11357 and under Grant No. DE-SC0017799 and Contract No. DE-FG02-97ER41041. Also, from the Fonds de la Recherche Scientifique-FNRS under Grant No IISN 4.4502.19, the ChETEC COST Action (CA16117), supported by COST (European Cooperation in Science and Technology), the IReNA AccelNet Network of Networks, supported by the National Science Foundation under Grant No. OISE-1927130 and from the World Premier International Research Centre Initiative (WPI Initiative), MEXT, Japan. This research used re- sources of ANL’s ATLAS facility, which is a DOE Office of Science User Facility.

[1] I. Ivans, et al., (2006). Ap. J. 645(1), 612-633.
[2] M. Rayet and M. Hashimoto., (2000). A&A 354, 740-748.
[3] M. P. Taggart, et al., (2019). Phys. Let. B. 798, 134894.
[4] J. Frost-Schenk. (2020). “Alpha capture reactions for abundance observations in nuclear astrophysics”. PhD Thesis. University of York.

Speaker: C. Angus (University of York & TRIUMF)

133-CJ_ANGUS-The_energy_levels_of_21Ne_and_the_s-process_in_rapidly_rotating_metal_poor_stars.pdf

15:30 The TUSCC project: What can elephants teach us about cancer prevention and treatment in humans

Although logic would suggest the contrary, it seems that cancer incidence is not related to body size (number of cells) and species life span (number of cell divisions). Large, long-living mammals, such as elephants, have no increased risk of developing cancer compared to smaller mammals with fewer cells and shorter lifespans. This lack of correlation between body size, life span and cancer risks is known in evolutionary biology as Peto's Paradox. Recent reports have shown that elephants have an expanded number of TP53 gene copies, a crucial tumour-suppressor gene encoding the tumour protein p53. However, the redundancy in tumour suppressor genes cannot resolve Peto’s paradox completely in elephants, since they should have developed a trade-off between the aggressive elimination of damaged cells and senescence due to depletion of their stem cell pool.

While limited research and experimental efforts have focused on resolving the paradox up to now, there are a growing number of alternative hypotheses that have been proposed. In the project “Tumour Suppression and Subdual of Cancer (TUSSC) in elephants”, we aim to investigate three alternative mechanisms (metabolism, inflammasome and telomere length) which could play an important role in cancer suppression by comparing captive and free-roaming elephants.

Here, we will present the first results of our project and highlight what implications Peto’s paradox could have for radiation protection and radiation therapy strategies. Blood samples were collected from elephants by experienced wildlife veterinarians in the Zoo of Naples (Italy) and at Botlierskop, a private game reserve with free-roaming elephants (South Africa). After collection and transport to the laboratories, the elephant blood samples were irradiated and cell death and DNA repair response was compared to human samples. In addition, comparative next generation sequencing will be performed on human and elephant blood samples, to investigate which specific pathways are up- or downregulated after radiation exposure. The results of the Annexin V/PI apoptosis assay illustrate that elephant cells go into apoptosis at much higher rates than human cells, even after exposure to doses as low as 0.125 Gy. DNA double-strand break (DSB) induction and repair was evaluated using the γ-H2AX foci assay. While no statistically significant difference could be observed in the number of DNA DSBs at 1 hour post-irradiation, the 24 hours result confirm that elephant cells repair the induced damage faster.

The first results of the project confirm the working mechanisms of the tumour suppressor gene and striking differences in DNA repair capacity between human and elephant cells. It is envisaged that this project could rapidly advance the development of new strategies for the prevention of radiation-induced cancers or the sensitization of cancer cells to radiotherapy. In addition, future experiments are planned with elephant fibroblast cells and carbon-ions, which will also increase our understanding of the role of TP53 in the DNA damage response after high-LET radiation.

Speaker: Charlot Vandevoorde (iThemba LABS)

228_C_Vandevoorde_The TUSCC project_What can elephants teach us about cancer prevention and treatment in humans.pdf

Friday, 24 September

09:45 → 11:15 Session 11: Neutron Physics, Nuclear Structure, Reactions and Dynamics

Convener: Sydney Gales (IPN Orsay)

09:45 Recent results from n_TOF

Based on an idea by Carlo Rubbia, the n_TOF facility at CERN has been operating during the last 20 years. it is a neutron spallation source, driven by the 20 GeV/c proton beam from the CERN PS accelerator. Neutrons in a very wide energy range (from GeV, down to sub-eV kinetic energy) are generated by a massive Lead spallation target feeding two experimental areas set at 185 meters (EAR1, horizonal with respect to the proton beam direction) and at 20 meters (EAR2, vertical) from the spallation source. Neutron energies for experiments are selected by the time-of-flight technique, (hence the name n_TOF), while the long flight paths ensure the possibility of doing very high-resolution measurements.

Over the course of two decades, over one hundred experiments have been performed by the n_TOF Collaboration, with applications ranging from nuclear astrophysics (synthesis of the heavy elements in stars, big bang nucleosynthesis, nuclear cosmo-chronology), to advanced nuclear technologies (nuclear data for applications, nuclear safety) to basic nuclear science (structure and decay of highly excited compound states).

During the planned shutdown of the CERN accelerator complex between 2019 and 2021, the facility went through a substantial upgrade with a new target-moderator assembly, refurbishing of the neutron beam lines and experimental areas. An additional measuring and irradiation station (the NEAR Station) has been envisaged and its capabilities for performing material test studies and new physics opportunities are presently explored.

An overview of the facility and of its experimental plan for future activities will be presented, with a particular emphasis on the most recent results and planning for the future.

Speaker: Alberto Mengoni (ENEA and INFN, Bologna, Italy)

10:15 Systematic study of neutron-deficient nuclei by beta-decay spectroscopy

Beta decay has a direct access to the absolute values of the Fermi and Gamow-Teller transition strengths. The comparison with complementary charge exchange reactions, such as the ($^3$He,t) reaction performed on the mirror stable targets at RCNP Osaka, allows us the investigation of fundamental questions related to the role of the isospin in atomic nuclei. A systematic study of proton-rich nuclei has been carried out by decay spectroscopy experiments with implanted radioactive ion beams (RIBs) at GANIL and RIKEN. We have obtained remarkable results [1-4], among which the discovery of the exotic $\beta$-delayed $\gamma$-proton decay in $^{56}$Zn [1] and the first observation of the 2$^+$ isomer in $^{52}$Co [3]. These studies were extended to higher masses and more extreme nuclear conditions at RIKEN thanks to the high-intensity RIBs available. An overview of the most important results will be presented, together with the new results on $^{60}$Ge and $^{62}$Ge [4] obtained from the RIKEN experiment.
[1] S.E.A. Orrigo et al., Phys. Rev. Lett. 112, 222501 (2014).
[2] S.E.A. Orrigo et al., Phys. Rev. C 93, 044336 (2016).
[3] S.E.A. Orrigo et al., Phys. Rev. C 94, 044315 (2016).
[4] S.E.A. Orrigo et al., Phys. Rev. C 103, 014324 (2021).

Speaker: Sonja Orrigo (IFIC (CSIC-UV))

10:35 Triaxial odd-odd nuclei at proton drip-line

The spontaneous proton emission from the nuclei at the proton drip-line is a unique tool to investigate the nuclear structure properties in extreme conditions. Furthermore, as the astrophysical rapid proton capture (rp) process is the inverse of proton emission, the study of the latter can provide insights into the possible paths of the rp process [1-3]. However, due to the short half-life, there is a lack of data in the exotic region. Complexities surge when one encounters odd-odd nuclei with triaxial deformation. Therefore, a robust theoretical framework is required to encounter these nuclei, which relies on the least number of freely adjustable parameters. With this motive, recently, we have developed a nonadiabatic quasiparticle approach within the core-particle coupling framework to study the triaxial odd-odd nuclei [4]. The matrix elements of the odd-odd system are written in terms of core energies through an appropriate transformation such that the experimental data of the core can be incorporated directly [5]. In addition, the residual neutron-proton (np) interaction is included in two reliable ways, namely, a constant potential form and zero-range interaction. The developed approach has been successfully applied [6] to interpret the data of recently observed proton emitter $^{108}$I [3]. We establish that triaxiality plays a significant role in the proton emission from $^{108}$I. Furthermore, the residual np interaction is crucial to conclude the ground state spin and parity of this nucleus, which is $1^{+}$ state. This approach is quite reliable for studying the fine structure in proton emission and chirality in triaxial odd-odd nuclei.
[1] C. Mazzocchi et al., Phys. Rev. Lett. 98, 212501 (2007).
[2] H. Suzuki et al., Phys. Rev. Lett. 119, 192503 (2017).
[3] K. Auranen et al., Phys. Lett. B 792, 187 (2019).
[4] P. Siwach et al., J. Phys. G: Nucl. Part. Phys. 47, 125105 (2020).
[5] S. Modi et al., Phys. Rev. C 95, 024326 (2017).
[6] P. Siwach et al., Phys. Rev. C 103, L031303 (2021).

Speaker: Pooja Siwach (Indian Institute of Technology Roorkee)

10:55 Measurement of the B(E2; 4$^+ \rightarrow $ 2$^+$)/ B(E2; 2$^+ \rightarrow $ 0$^+$) ratio in 164W

Recent lifetime measurements revealed that the B(E2)$_{4^+/2^+}$ ratio is far less than unity in several nuclei in the mass region 160 ≤ A ≤ 170 namely $^{166}$W [1], $^{168}$Os [2], $^{170}$Os [3], and $^{172}$Pt [4]. From a theoretical point of view, the origin and the underlying structure of this anomalous behavior remains unexplained. On the other hand, a quantum phase transition from seniority-conserving structure to a collective regime as a function of neutron number around N ≈ 90 - 94 has been proposed for these nuclei from phenomenological point of view [4]. In the present work, we aimed to extend our investigation of the anomalous B(E2; 4$^+ \rightarrow $ 2$^+$)/ B(E2; 2$^+ \rightarrow $ 0$^+$) ratio phenomenon this mass region in order to provide more data for the future theoretical calculations. We chose $^{164}$W as a good candidate to investigate because, it has a pivotal position with N = 90 to test the hypothesis of a quantum phase transition as the mechanism for the B(E2)$_{4^+/2^+}$ anomaly. We used the DPUNS [5] plunger device in conjunction with the RITU gas-filled separator [6] and the JUROGAM II and GREAT [7] spectrometers for the measurement of mean lifetimes of excited states in $^{164}$W. The fusion evaporation reaction $^{106}$Cd($^{60}$Ni,2p2n)$^{164}$W* at a beam energy of 270 MeV provided an initial recoil velocity v/c of 3.3%. The analysis of the data revealed that 164W has a similar B(E2)$_{4^+/2^+}$ = 0.56(13) < 1 anomaly as in the $^{166}$W, $^{168}$Os, $^{170}$Os, and $^{172}$Pt nuclei. Experimental B(E2) values have been compared to the state-of-the-art beyond-mean-field calculations. However, the theoretical predictions disagree with experimental findings. In the present work, details of the experimental procedure and analysis steps will be explained and the results for the lifetime measurements of first excited 2$^+$ and 4$^+$ states will be presented.
This work has been supported by the UK Science and Technology Facilities Council under grants ST/P004598/1, ST/L005670/1 and ST/L005794/1; the Scientific and Technological Research Council of Turkey (TUBITAK Project No: 117F508); the EU HORIZON2020 programme “Infrastructures”, project number: 654002 (ENSAR2) and by the Academy of Finland under the Finnish Centre of Excellence Programme (Nuclear and Accelerator Based Physics Pro-gramme at JYFL). The UK/France (STFC/IN2P3) Loan Pool and GAMMAPOOL network are acknowledged for the HPGe escape-suppressed detectors of the JUROGAM II array.
[1] B. Saygı et al., Phys. Rev. C96, 021301 (2017).
[2] T. Grahn et al., Phys. Rev. C94, 044327 (2016).
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Speaker: Bahadir Saygi

11:15 → 11:30 Tea/Coffee/Short Break

11:30 → 13:00 Session 12: Nuclear Structure, Reactions and Dynamics

Convener: Claes Fahlander (Lund University)

11:30 Nuclear Structure Studies at the NSCL

The National Superconducting Cyclotron Laboratory on the campus of Michigan State University provided fast, stopped, and reaccelerated beams of rare isotopes for nuclear science research. This presentation will give an overview of the nuclear structure program with representative examples showcasing a complementary set of experimental techniques.

Speaker: Alexandra Gade (NSCL/FRIB)

226-A_Gade-Nuclear_Structure_Studies_at_NSCL.mp4

12:00 Damping of the ISGMR in 90Zr and 120Sn

Giant Resonances (GRs) are considered to be high frequency shape-vibrations of the nucleus. Since the new millennium it became apparent that the IsoScalar Giant Quadrupole Resonance (ISGQR) exhibits fine structure that is independent of probe, and soon after that it was shown that other GRs also exhibit such fine structure. As such, this fine structure as an additional GR observable has been shown to be a useful tool to determine the damping mechanism of different shape-vibrations using the Wavelet Analysis technique.

The ISGMR was excited in $^{90}$Zr and $^{120}$Sn by using inelastic $\alpha$-particle scattering measurements acquired with an $E_\alpha = 200$ MeV beam at $\theta_{\text{Lab}} = 0^0$ and $4^0$. The high energy-resolution K$600$ magnetic spectrometer at iThemba LABS was used to detect the scattered alpha particles and an experimental energy-resolution of $\sim 70$ keV (FWHM) was achieved. This enabled the fine structure in the excitation energy region of the ISGMR to be investigated. Due to the limitations in angular acceptance and resolution, the $E0$ strength distributions in the present study was determined using the Difference-of-Spectra (DoS) method. Here, the $L = 0$ multipole excited (ISGMR $E0$ strength) has a maximum at $\theta_{\text{Lab}} = 0^0$ allowing the background from all other multipoles to be subtracted using an angle cut from the $\theta_{\text{Lab}} = 4^0$ measurements where the $L = 0$ has a deep minimum.

The aim of the work to be presented is to investigate the damping mechanism of the ISGMR in $^{90}$Zr and $^{120}$Sn. The $E0$ strength distribution in $^{90}$Zr and $^{120}$Sn will be discussed and compared to theoretical predictions from the Phonon-Phonon Coupling (PPC) model.

Speaker: Armand Bahini (University of the Witwatersrand, Johannesburg)

144_Armand_Bahini_Damping_of_the_ISGMR_in_90Zr_and_120Sn.pdf

ANPC_abstract.pdf

12:20 Microscopic description of isoscalar giant monopole resonance: The case of 132Sn

The study of nuclear giant resonances has long been a subject of extensive theoretical and experimental research. The multipole response of nuclei far from the beta-stability line and the possible occurrence of exotic modes of excitation present a growing field of research. In particular, the study of the isoscalar giant monopole resonances (ISGMR) in neutron-rich nuclei is presently an important problem not only from the nuclear structure point of view [1] but also because of the special role they play in many astrophysical processes such as prompt supernova explosions [2] and the interiors of neutron stars [3]. One of the successful tools for describing the ISGMR is the quasiparticle random phase approximation (QRPA) with the self-consistent mean-field derived from Skyrme energy density functionals (EDF) [4]. Due to the anharmonicity of the vibrations there is a coupling between one-phonon and more complex states [5]. The main difficulty is that the complexity of calculations beyond standard QRPA increases rapidly with the size of the configuration space, and one has to work within limited spaces. Using a finite rank separable approximation for the residual particle-hole interaction derived from the Skyrme forces one can overcome this numerical problem [6-8].
In the present report, we study the effects of phonon-phonon coupling on the monopole strength distributions of neutron-rich tin isotopes. Using the same set of the EDF parameters, we describe available experimental data for 118,120,122,124Sn [9] and give prediction for 132Sn [10]. The effects of the phonon-phonon coupling leads to a redistribution of the main monopole strength to lower energy states and also to higher energy tail. We analyze thoroughly the properties of the low-energy 0+ spectrum of two-phonon excitations of 132Sn. We give prediction for the excitation energy of the lowest two-phonon state around Ex=8 MeV in comparison to 11.5 MeV in the case of the lowest 0+ state within the random phase approximation.

This work was partly supported by the Heisenberg-Landau (Germany-BLTP JINR) program and the National Research Foundation of South Africa (Grant No.129603).

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5. V.G. Soloviev, Theory of Atomic Nuclei: Quasiparticles and Phonons, Bristol/Philadelphia (1992).
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7. A.P. Severyukhin, V.V. Voronov, N.V. Giai, Phys. Rev. C 77, 024322 (2008).
8. A.P. Severyukhin, V.V. Voronov, N.V. Giai, Eur. Phys. J. A. 22, 397 (2004).
9. T. Li, U. Garg, Y. Liu et al., Phys. Rev. C 81, 034309 (2010).
10. N.N. Arsenyev, A.P. Severyukhin, Universe 7, 145 (2021).

Speaker: Nikolay Arsenyev (Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research)

12:40 Polarizability of $^{40}$Ca and $^{48}$Ca: Implications for the density dependence of the symmetry energy

The dipole polarizability of $^{40}$Ca has been extracted from a zero-degree (p,p$^\prime$) experiment at RCNP [1]. Together with results from a previous experiment on $^{48}$Ca [2] it serves as a test of state-of-the-art ab initio [3,4] and EDF [5] calculations. From the good agreement obtained for both methods one can derive limits on the density dependence of the symmetry energy. These are clearly at variance with those derived [6] from the recently published result of the PREX-II experiment [7].

[1] P. von Neumann-Cosel and A. Tamii, Eur. Phys. J. A 55, 110 (2019).
[2] J. Birkhan et al., Phys. Rev. Lett. 118, 252501 (2017).
[3] J. Simonis, S. Bacca, and G. Hagen, Eur. Phys. J. A 55, 241 (2019).
[4] S. Kaufmann et al., Phys. Rev. Lett. 124, 132502 (2020).
[5] P.-G. Reinhard, X. Roca-Maza, and W. Nazarewicz, arXiv:2105.15050.
[6] D. Adhikari et al., Phys. Rev. Lett. 126, 172502 (2021).
[7] B.T. Reed et al., Phys. Rev. Lett. 126, 172503 (2021).

Supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - Project-ID 279384907 - SFB 1245.

Speaker: Peter von Neumann-Cosel (Institut f\"ur Kernphysik, Technische Universit\"at Darmstadt)

13:00 → 13:30 Meal/Long Break

13:30 → 15:45 Workshop Session 3: What new directions could stable ion beams and novel instrumentation bring to further our understanding of nuclear reaction dynamics and the fission process through gamma-ray spectroscopy?

Convener: Vandana Nanal (TIFR)

13:30 Physics opportunities with isotopically identified Fission Fragments

Speaker: Antoine Lemasson (GANIL)

13:55 Q&A with Discussion

Speaker: Vandana Nanal (TIFR)

14:05 Recent studies of heavy ion transfer reactions using large solid angle magnetic spectrometers

Speaker: Suzana Szilner (dr)

ANPC21-Szilner-forpdf.pdf

14:30 Q&A with Discussion

Speaker: Vandana Nanal (TIFR)

14:40 Tea/Coffee/Short Break

14:55 Angular momentum generation in nuclear fission

Speaker: Jonathan Wilson (IPN Orsay)

15:20 Q&A with Discussion

Speaker: Vandana Nanal (TIFR)

15:30 Summary Discussion

Speaker: Vandana Nanal (TIFR)

15:45 → 16:00 Conference Closing