Xenon detector experiments have provided some of the most sensitive searches of physics beyond the standard model (BSM). These campaigns have placed emphasis on observing dark matter interactions and/or neutrinoless double beta decays (0ν2β). Several next-generation experiments aim to build on this work and probe for BSM physics with significantly improved sensitivity. In relation to the...
Coulomb excitation is a well-established and powerful experimental technique for probing the structure and dynamics of nuclei in a model-independent way. The technique is especially sensitive to the quadrupole shape degrees of freedom as it selectively excites low-lying collective states with cross sections that directly measure the E2 matrix elements involved in the excitation. In particular,...
Nuclei along N=20 provide an excellent region to investigate the change in nuclear structure and interactions. From their evolution from the doubly magic nucleus $^{40}$Ca through to the Z=16 and Z=14 nuclei $^{36}$S and $^{34}$Si, respectively, to $^{32}$Mg with a deformed $2p-2h$ intruder ground state [1]. The mechanism responsible for the change in shell structure is not well understood and...
The AGATA-MUGAST-VAMOS set-up, which was recently available at GANIL
for a direct reaction campaign, combined the state-of-the-art gamma-ray
tracking array AGATA with the highly-segmented silicon array MUGAST and
the large-acceptance magnetic spectrometer VAMOS. The mechanical and
electronics integration provided a maximum efficiency for each device.
The superb sensitivity of the complete...
Due to their unique analytical and irradiation capabilities, ion beam accelerators play a major role in solving problems of modern society related to environmental pollution and monitoring, climate change, water and air quality, forensics, cultural heritage, agriculture, development of advanced materials for energy production via fission or fusion, and many other fields. Moreover, particle...
A significant part of the upgrade of the Dubna Radioactive Ion Beams facility was putting in operation a new high acceptance device - the ACCULINNA-2 fragment separator, http://flerovlab.jinr.ru/accullina-ii/. It’s the new in-flight facility for operating with low energy 30-60 AMeV primary beams with 3 ≤ Z ≤ 36 delivered by U-400M cyclotron. The new separator provides high quality secondary...
The study of nuclear statistical properties is of importance not only in nuclear waste transmutation [1] and nuclear fuel cycles [2] but also in nuclear structure and nuclear astrophysics studies [3]. These statistical properties - the nuclear level density (NLD), which describes the number of available energy levels in a nucleus for a given excitation energy, and the photon strength...
Great progress has been made regarding our understanding of heavy-element nucleosynthesis in recent years. In particular, the 2017 discovery of a neutron-star merger with its kilonova confirmed that such astrophysical sites can produce heavy elements through the rapid neutron-capture process. At the same time, as more and more high-quality observations become available, the heavy-element...
Pioneering nuclear reaction studies of astrophysical interest have been carried out at the Laboratory for Underground Nuclear Astrophysics (LUNA) for about three decades (see [1] for a recent review). Shielded by 1.4 km of rock under the Gran Sasso mountain, LUNA benefits from a million-fold reduction in cosmic-ray induced background compared to surface laboratories. This has made it possible,...
The Oslo Method is a powerful tool that allows for detailed studies of the Nuclear Level Density (NLD) and $\gamma$-ray strength function ($\gamma$SF) at energies below the neutron separation energy. In the last decade, several Oslo Method experiments have been performed at iThemba LABS, most notably with inverse-kinematics. Coupling the Oslo Method with inverse kinematics allows for study of...
Abstract
As much as nucleosynthesis or element formation is concerned, almost all the nuclei heavier than iron have been made in part by the slow neutron capture and the rapid neutron capture processes (≈ 50% each), respectively known as the s- and r- processes [1].
The neutron capture reactions 192Ir(n,γ)193Ir and 193Ir(n,γ)194Ir are indirectly studied by analysing data obtained from the...
Particle accelerator institutes have extensively contributed to biomedical research programs worldwide, which are of particular importance for their societal benefit and impact on human health. Ionizing radiation possesses the ability to directly damage the DNA structure of cells, causing DNA breaks, which can ultimately result in cell death.
This property has been used since many years for...
Radiation damage to the central nervous system (CNS) has become an intriguing health problem of the last decades, largely due to the issues of radiation hazard of human deep-space flights and brain radiation therapy issues. In spite of recent intensive research in this field, the fundamental properties of regulatory pathways associated with radiation-induced CNS impairments remain mostly...
The talk will cover recent initiatives and options be provided by NICA facility for applied research be performed with ion beams. NICA (Nuclotron-based Ion Collider fAсility) is a new accelerator complex designed at the Joint Institute for Nuclear Research to study properties of dense baryonic matter. Besides the fundamental physics issues, the NICA team is also working under construction of...
Knockout reaction studies have historically been used as an ideal mechanism to probe the nature of nuclear structure, especially single-particle properties of nuclei by means of proton knockout reactions such as (p, 2p). Nucleon-induced knockout reactions have also proven useful to unravel details of the nucleon-nucleon interaction, as well as the notion of ground state α-clustering in nuclei...
Proton-induced knockout reactions provide a direct mean of studying the single particle or cluster structures of target nuclei. However, due to the nature of hadron probe, these reactions can suffer significant disturbances from the nuclear surroundings and the quantitative theoretical treatment of such processes can also be challenging. In this talk, firstly we review the experimental and...
The RI Beam Factory (RIBF) is a third-generation in-flight facility, designed and optimized for the RI beam production by uranium fission. High intensity beams available over a wide region of the nuclear chart by the BigRIPS separator, together with the three spectrometers, namely ZeroDegree, Samurai and SHARAQ/OEDO each having a specific advantage, make a powerful platform for reaction...
The 2+2 state in non-doubly-magic, even-even nuclei is commonly interpreted as due to a collective excitation. In the vibrational and rotational limits, this state originates from vibrations around the ground-state shape. Even though these basic paradigms are known to represent only a first-order approximation of the nuclear structure, they are still used for classifying isotopes throughout...
It was recently proposed that odd-mass triaxial nuclei can exhibit wobbling motion at low spins. Excited bands identified as wobbling were reported in several nuclei, including two gold isotopes; $^{183}$Au and $^{187}$Au. These Au isotopes are good candidates for studying such phenomena as the nuclei in this mass region are strongly affected by the triaxial degree of freedom [1 - 2]. An...
Isospin symmetry – the neutron-proton exchange symmetry rooted in the concepts of charge symmetry and charge independence of the nuclear force – is one of the key concepts in nuclear physics. It results in beautiful and simple symmetries in the otherwise complex behaviour of nuclei, and examination of how those symmetries are broken can, in turn, shed light on the properties of the...
Introduction
The cyclotron-based production of radionuclides for medicine is one of the research activities carried out in the framework of the SPES (Selective Production of Exotic Species) project at the Legnaro National Laboratories of the National Institute for Nuclear Physics (INFN-LNL). The heart of SPES is the 70 MeV proton-cyclotron with a dual-beam extraction, installed in 2015 in a...
The aim of this study is to evaluate the suitability of ADAM10 as a target for imaging cervical cancer using a 123I-radiolabelled ADAM10 inhibitor. A Disintegrin and Metalloproteinases (ADAMs) exhibit proteolytic activity like matrix metalloproteinases and ADAM10 sheds a range of membrane-bound proteins that play a role in cancer progression, radioresistance and the tumor micro-environment....
Considering the upcoming long-duration spaceflight missions, a better understanding of the impact of spaceflight exposome on human health is urgently warranted. Consequently, particle accelerator facilities implement ground-based, Radiobiology experiments investigating the health effects of simulated-space environments with simulated-psychological or physical stressors. iThemba LABS is such a...
The gamma-ray decay of nuclear states in the quasi-continuum offers valuable insights into nuclear structure effects and constraints on nucleosynthesis processes. Measurement of Nuclear Level Densities (NLDs) and Photon Strength Functions (PSFs) has played a pivotal role, and will continue to do so, as we enter a highly promising era for innovative measurements. This is primarily due to the...
This study aims to understand the Pygmy Dipole Resonance (PDR) in the deformed 154Sm nucleus. Despite previous efforts, the interpretation of the behavior and nature of this low-energy resonance remains unclear with respect to the effects of neutron excess and deformation in nuclei. This further limits the predictive power of exotic nuclei properties. The current study uses the (γ, γ′)...
The low-lying E1 strength which has been termed the pygmy dipole resonance (PDR), manifests as a concentration of 1$^{-}$ states below and around the neutron threshold. It has thus far been observed in neutron-rich nuclei and its study may have implications on the nuclear equation of state and nucleosynthesis. Since its discovery, there has been a great deal of work in an attempt to understand...
Quasicontinuum gamma decay following compound reactions - commonly called Oslo method - is probably the most important source of information on the gamma strength functions and level densities of nuclei below particle threshold. A fundamental assumption in the analysis of Oslo-type data (and in fact all astrophysical reaction network calculations) is the generalized Brink-Axel (BA) hypothesis,...
The observation of resonance-like structure in the electric dipole response of heavy nuclei at energies around or below the neutron, commonly termed pygmy dipole resonance (PDR), has been a topic leading to considerable experimental and theoretical activities in recent years [1-4]. The interest has been triggered by attempts to understand the underlying structure but also because of its impact...
Neutron-rich nuclei with A ~ 190 provide a characteristic testing ground for microscopic theories of nuclear structures. There are quite a few indications that a prolate-oblate shape transition takes place at around N = 116 in this region [1, 2].
The microscopic description of anharmonicities in nuclear quadrupole collective motions, in terms of the fermion degrees of freedom, is a...
nEXO is a next-generation experiment that aims to observe the neutrinoless double beta decay of $^{136}$Xe to $^{136}$Ba. The experiment will use 5 tonnes of liquid xenon (LXe) enriched to 90% in $^{136}$Xe in a single-phase, monolithic time projection chamber (TPC). Ionization electrons and scintillation light will be detected with a segmented anode and an array of VUV-sensitive silicon...
The study of the total cross sections for the reactions involving neutron-rich weakly bound nuclei makes it possible to obtain information on their structure (halo, skin, clustering, etc.) and its manifestation in nuclear reactions.
For example, the outer neutrons of the ${}^9$Li nucleus with an energy of separation of 4 MeV have a compact space distribution that may be called skin. The...
"Astrophysics is applied nuclear physics". This statement of Willy Fowler, the father of nuclear astrophysics, summarizes that nuclear processes are at the origin of the synthesis of the elements in the Universe and also the engine of the astrophysical objects which produce them. This includes the synthesis of the lightest elements during the Big Bang, but also the evolution of stars during...
The abundance of $^{26}$Al carries a special role in astrophysics, since it probes active nucleosynthesis in the Milky Way and constrains the Galactic core-collapse supernovae rate. It is estimated through the detection of the 1809~keV $\gamma$-line of the daughter $^{26}$Mg and from the superabundance of $^{26}$Mg in comparison with the most abundant Mg isotope (A=24) in meteorites. For this...
Elemental abundances are excellent probes of classical novae (CN). Sensitivity studies show that $^{38}$K($p$,$\gamma$)$^{39}$Ca reaction-rate uncertainties modify the abundance of calcium by a factor of 60 in CN ejecta. Existing direct [1,2] and indirect measurements [3,4] are in contradiction concerning the energies and strengths of important resonances in the $^{38}$K($p$,$\gamma$)$^{39}$Ca...
Neutron capture nucleosynthesis via s-, r- and i-process are responsible for the production of elements heavier than Fe in the Universe.
Nucleosynthesis predictions can be affected by both the free parameters of the astrophysical models, which do not allow to accurately reproduce the neutron densities in stellar environments, and the uncertainties of the nuclear physics quantities employed in...
The PANDORA (Photo-Absorption of Nuclei and Decay Observation for Reactions in Astrophysics) project focuses on the experimental and theoretical analysis of photo-nuclear reactions involving light nuclei with a mass below A = 60. This is of particular importance in the scope of ultra-high-energy cosmic ray research where the main mode of energy attenuation as it travels through the cosmos is...
The K600 magnetic spectrometer and the CAKE silicon detector array form a powerful tool for coincidence measurements in many nuclear physics measurements including nuclear astrophysics. These instruments have been used, among others, in studies measuring proton decays from $\alpha$-unbound states in $^{22}$Mg through the $^{24}$Mg$(p,t)$$^{22}$Mg reaction to study the...
The experimental evidence points to the existence, at short distances, of strongly correlated neutron-proton pairs much like they are in the deuteron or in free scattering processes.
As it moves through the nuclear medium, a “bare” nucleon in the presence of the nucleon-nucleon interaction becomes “dressed” in a quasi-deuteron cloud, about 20% of the time. Our phenomenological analysis of...
The proton-induced $\alpha$ knockout reaction, ($p,p\alpha$), is a powerful probe of the $\alpha$ formation in the nucleus [1]. We have shown that a modern theoretical calculation of the $\alpha$ amplitude in the $^{20}$Ne ground state combined with the ($p,p\alpha$) reaction calculation by the distorted wave impulse approximation can quantitatively reproduce the existing experimental data...
Formation of clusters in nuclei is a topic of great interest and fundamental importance throughout the history of nuclear physics. In light nuclei, development of cluster structure in states close to the corresponding decay threshold is a well established phenomenon, and significant progress has been made in search for novel cluster states in light nuclei, such as the α-condensate states (e.g...
Nuclear physics research is at the dawn of a new era. After the Big Bang and billions years of evolution, the universe has provided us around 2000 nuclei. Based on the information from these nuclei, nuclear theory has been established in order to understand the structure of the nucleus. The steady progress over the past twenty years in the development of high intensity stable beams and of...
Halo nuclei are fascinating short-lived nuclear systems found near the driplines.
In standard reaction models, halo nuclei are usually described as an inert core with one or two weakly bound nucleons. However, some breakup data suggest that the dynamics of the reaction is influenced by the excitation of the core to its excited states in a significant way [1].
Halo-EFT has been shown to...
One of the yet unsettled problems in heavy-ion fusion near and below the barrier is the relative influence of nucleon transfer channels and couplings to collective modes on the cross sections. We recall two relevant papers [1] where that influence, and the moments of fusion-barrier distributions were investigated.
In this contribution, we present a new analysis of several systems, based on...
Beta-decaying, high-spin, spin-trap isomers have been observed in 96Y, 98Y and 100Y with half-lives ranging from 9 to 0.9 seconds [Ab08,Ch20,Si21]. However, in 102Y there are two beta-decaying states which have similar half lives (t 1/2 = 360(40) ms [Sh83] and 300(10) ms [Hi91]) and a small energy difference, making it difficult to measure their relative energy and to ascertain if the...
In 2019, a new project focused on implementing the MAGNEX Focal Plane Detector (FPD) at the K600 spectrometer facility at iThemba LABS was started with the aim to facilitate experiments involving heavy-ion beams. The primary intention was to investigate Double Charge Exchange (DCE) reactions and competing quasi-elastic channels at various incident energies, expanding upon the research...
The development of $\gamma$-ray energy-tracking arrays using highly segmented High Purity Germanium (HPGe) detectors is currently the technological frontier of high-resolution gamma-ray spectroscopy in modern nuclear physics [1]. The tracking capability of such arrays strongly depends on the performance of the Pulse Shape Analysis (PSA), which uses the position-dependent response of the...
Accelerator driven neutron sources with high brilliance neutron provision present an attractive alternative to classical neutron sources of fission reactors and spallation sources to provide scientist with neutrons to probe and analyze the structure and dynamics of matter. With the advent of high current proton accelerator systems, a novel class of such neutron facilities can be established...
Artificial Intelligence (AI) and Machine Learning (ML) are rapidly developing fields providing data-driven algorithms to predict, classify, and make decisions based on data. Nuclear Physics Research is data-driven and AI/ML techniques have been implemented for experiment and accelerator control, in theoretical applications, and in data processing and analysis. These algorithms open...
Sylvester Agbemava1, Eric Flynn1,2, Daniel Lay1,2, Kyle Godbey1, Witold Nazarewicz1,2
1FRIB Laboratory, Michigan State University, East Lansing, Michigan 48824, USA.
2Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA.
Fission is a fundamental nuclear decay that plays an important role in many areas of science. Recently, significant...
Deuteron-induced nuclear reactions are typically described within a Faddeev three-body model consisting of a neutron, proton, and the nucleus interacting through pairwise forces. While Faddeev techniques enable the exact description of the three-body dynamics, their predictive power is limited in part by the omission of irreducible three-body nucleon-nucleon-nucleus forces. An alternative...
Electron scattering and rare isotopes are unique complementary techniques that provide powerful magnifying glasses to probe the interactions between nucleons inside nuclei. Over more than a quarter century, the 4 GeV and now 12 GeV (un)polarized electron beam of the Thomas Jefferson National Accelerator Facility (Newport News, Virginia, USA) has unraveled unprecedented insights into nuclear...
The level density of 2+ states in 208Pb and 120Sn nuclei have been extracted in the energy region of the isoscalar giant quadrupole resonance (ISGQR) from a fluctuation analysis of high-energy-resolution (p,p’) data taken at incident energies of 200 MeV at the K600 magnetic spectrometer of iThemba LABS, South Africa. The shape of the background was determined from the discrete wavelet...
Background: In highly deformed nuclei, there is a noticeable coupling of the Isoscalar Giant Monopole Resonance (ISGMR) and the $K = 0$ component of the Isoscalar Giant Quadrupole Resonance (ISGQR), which results in a double peak structure of the isoscalar monopole (IS0) strength (a narrow low-energy deformation-induced peak and a main broad ISGMR part). The energy of the narrow low-lying IS0...
The investigation of compressional-mode giant resonances, specifically the isoscalar giant monopole resonance (GMR), continues to captivate the interest of nuclear physicists. This research is centered on the meticulous analysis of isoscalar monopole resonances within the 112-124Sn isotopic mass chain, aiming to glean profound insights into nuclear matter compressibility. The lingering...
The cross sections of proton-nucleus scattering at eneries from 200 to 1000 MeV are calculated within the microscopic model of folding optical potential. Such potential is determined by the amplitude of scattering of an incident proton on the bound nuclear nucleon which itself depends on three parameters, namely the total nucleon-nucleon scattering cross section, the ratio of real to imaginary...
There continues to be a growing need for new compact neutron spectrometers, driven mainly by the requirements for dosimetry in hadron therapy, aircraft, spacecraft, future extra-terrestrial bases, and around high energy accelerator facilities. For dosimetry in the upper atmosphere and in space, neutrons in the energy range exceeding 100 MeV need to be measured. Since neutrons are seldom ...
Silicon is one of the important elements used in modern technics. Information about gamma-rays spectrum of silicon can be used in elemental analysis of various objects. The usage of compact D-T neutron generators with an energy of 14.1 MeV makes it possible to create compact portable setups, as well as to implement the tagged neutrons method by detecting the accompanying alpha particle emitted...
The heavy neutron rich nuclei are very important for nuclear physics investigations, for the understanding of astrophysical nucleosynthesis and r-process. In this region is located the closed neutron shell N=126 which is the last so-called “waiting point”. Study of the structural properties of nuclei along the neutron shell N = 126 could also contribute to the present discussion of the...
The isospin asymmetry of neutron-rich nuclei is expected to impact the excitation energy spectra of such nuclei. The resulting exotic excitation modes which may occur are thus considered to be related to the existence of a neutron excess. The soft monopole resonance, simplistically viewed as the compression of dilute neutron matter in the region of the neutron skin, represents a possible...
The atomic nuclei, although they are quantal objects, may exhibit many features, which are known from the macroscopic world. To one of them belong different types of collective vibration, known as Giant Resonances, or recently studied, and important for the understanding of the creation of elements in the Universe, so called Pygmy Resonances. The studies of the gamma decay of the Giant and...
Director: Prof Makondelele Victor Tshivhase
As the sole research infrastructure of its kind in the African continent, iThemba LABS has become the hub to a vibrant research, human capital development, and collaboration network for nuclear science that includes the South African universities, research institutions and international counterparts.
The iThemba LABS K=200 separated sector...
The time evolution of the nuclear density of the fissioning system $^{240}Pu$
during the scission process is obtained from the time-dependent superfluid
local-density approximation (TDSLDA) to the density functional theory.
A nuclear energy density functional based on the Skyrme force Skm* is used.
The duration of the scission process $\Delta t$ as well as the neck
radius ($r_{min}$) of...
Neutron stars are the most mysterious objects in the universe, with a radius of the order of 10 km and masses that can reach two solar masses. In 2017, a gravitational wave was detected (GW170817) and its source was identified as the merger of two neutron stars. Later on, a mass-gap object (either a neutron star or a black hole) was identified in the GW190814 event. To understand neutron...
The Xe nuclei with mass A < 120 are perfectly placed to study the octupole correlations phenomena. For these nuclei, the presence of octupole driving h11/2 and d5/2 orbitals near the Fermi surface make them suitable to exhibit octupole correlation. Other than Xe nuclei such octupole correlations have also been reported in several other isotopes of Cs and Ba having N < 70. In previous high spin...
Comparative analyses of evaporative light particle energy and angular distributions within the Statistical Model (SM) framework indicate nuclear deformations at high spin significantly larger than those predicted by the Rotating Liquid Drop Model. Examples of light N=Z systems showing this behaviour are the 56Ni, 44Ti and 40Ca nuclei.
The clustering might be an important structural feature....
The abstract is attached in the pdf format
Quasi free scattering in inverse kinematics is a powerful tool allowing to explore the nuclear landscape at its outskirts.
The inverse kinematics allows the full detection of weakly and strong bound states in complete kinematics (1) through the detection of gammas and particle unstable states through the invariant mass method.
The ALADiN-LAND reaction setup fed by the FRS fragment...
V.O. Nesterenko
Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna, Moscow region, 141980, Russia
A toroidal dipole mode is a general phenomenon pertinent to both classical and quantum systems. In conventional fluid dynamics, this turbulence-induced mode is associated with the simplest vortical flow called Hill’s vortex [1]. In solid-body physics...
