African Nuclear Physics Conference

1 Jul 2019, 08:00 → 5 Jul 2019, 17:00 Africa/Johannesburg

mathis wiedeking (itl)

                                                              Group Photo - delegates at ANPC2019

The first in the African Nuclear Physics Conference (ANPC) series combines a topical nuclear physics conference with working group sessions aimed at focused discussions on select open questions in nuclear physics.

The ANPC will be held from Monday July 1, 2018 2019 to Friday July 5, 2019 at the Protea Hotel Kruger Gate at Kruger National Park in South Africa.

Please visit the website at http://www.anpc2019.tlabs.ac.za for more information and for the submission of abstracts by 3 March 2019.

The main topics of the ANPC 2019 conference are:

• Nuclear Astrophysics
• Nuclear Structure, Reactions and Dynamics
• Fundamental Interactions
• Neutron Physics
• Heavy Ion Physics
• Applied Nuclear Physics
• New Facilities and Instrumentation

The topic for the working group sessions is:

• Low-lying Dipole Modes of Excitation in Nuclei

 

We are looking forward to meeting you at Kruger National Park and please do not hesitate to contact us on anpc2019@tlabs.ac.za.

Local Organizing Committee ANPC 2019:

Faїçal Azaiez (chair)

Naomi Haasbroek

Ntombizonke Kheswa

Vincent Kheswa

Elena Lawrie

Rudolph Nchodu

Retief Neveling

Sifiso Ntshangase

Nico Orce

Luna Pellegri

Christine Steenkamp

Iyabo Usman

Mathis Wiedeking (co-chair)

Michelle Van Der Ventel-Bark

Hombakazi Wanana

 

 

 

anpc19-program-22may19.pdf

ANPC_Kruger19_1st_circular.pdf

ANPC_Kruger19_2nd_circular.pdf

ANPC_Kruger19_3rd_circular.pdf

ingonyama_ANPC2019h.jpg

Kruger2019 Accommodation form.pdf

Monday, 1 July

08:20 → 08:30 Opening and Welcome

09:45 → 10:00 Process and Stellar Weak Interaction Rates of Waiting Point Nuclei

The stellar weak interaction rates of proton-rich N≃Z nuclei in the A ∼70 mass region play a critical role during the rapid proton capture process (rp process) in type-I x-ray bursts taking place on the surface of neutron stars accreting hydrogen/helium-rich material from a low-mass close companion star. Nucleosynthesis in explosive hydrogen burning at high temperatures and densities is characterized mainly by the rp-process, a sequence of proton captures and weak interaction processes, β+ decays and continuum electron captures. An essential role for the rp-process reaction network studies is played by the waiting point nuclei like 68Se and 72Kr on which our studies were focused. The competition between the proton capture rates and the rates of the weak interaction processes at the waiting points affects the process significantly influencing the nuclear energy production rate and consequently the luminosity curves, direct observables of a type I x-ray burst. This competition also determines the burst time scale, the extent of the abundance flow to heavier masses as well as the final composition of the burst ashes.

Self-consistent nuclear structure models able to describe the properties of the experimentally accessible proton-rich nuclei are needed to predict the characteristics of nuclei beyond the experimental reach. Robust predictions on Gamow-Teller strength distributions for the ground state and the thermally populated low-lying excited states in the stellar environment, temperature dependence of the β + -decay rates as well as temperature and density evolution of the continuum electron capture rates during the rp-process are needed to realistically evaluate the effects of weak interaction rates of waiting point nuclei on nucleosynthesis in x-ray bursts. We investigated the impact of complex Excited Vampir beyond-mean-field predictions of stellar weak interaction rates of 68 Se and 72 Kr nuclei dominated by shape coexistence and mixing [1,2] on the rp-process in type-I x-ray bursts.

To explore the influence on burst simulations we used a post-processing approach based on a one-zone model that was adjusted to match a 1-D multizone hydrodynamic result. We performed a series of calculations based on different accreted compositions of hydrogen/helium mixing and metallicity. A comparison of the results obtained using the complex Excited Vampir predictions to the ones based on standard values for the β + -decay rates is outlined discussing the energy generation rates, the hydrogen and helium consumption, and the abundance flow to Sn isotopes reached during the burst. The results are relevant steps towards improved estimates of x-ray burst nucleosynthesis, and consequently, of the final abundances of the x-ray bursts required for modelling neutron star crust properties.

[1] A. Petrovici, O. Andrei, Eur. Phys. J. A 51, 133 (2015).
[2] A. Petrovici, O. Andrei, A. Chilug, Phys. Scr. 93, 114001 (2018).

Speaker: Prof. Alexandrina Petrovici (IFIN-HH)

ANPC2019_APetrovici-web.pdf

10:15 → 10:30 Photoneutron reaction cross section measurements on 94Mo and 90Zr relevant to the p-process nucleosynthesis

The photodisintegration cross sections for the 94Mo(γ,n) and 90Zr(γ,n) reactions have been experimentally investigated with quasi-monochromatic photon beams at the High Intensity γ-ray Source (HIγS) facility of the Triangle Universities Nuclear Laboratory (TUNL). The energy dependence of the photoneutron reaction cross sections was measured with high precision from the respective neutron emission thresholds up to 13.5 MeV.These measurements contribute to a broader investigation of nuclear reactions relevant to the understanding of the p-process nucleosynthesis. The results are compared with the predictions of Hauser-Feshbach statistical model calculations using two different models for the dipole γ-ray strength function. The resulting 94Mo(γ,n) and 90Zr(γ,n) photoneutron stellar reaction rates as a function of temperature in the typical range of interest for the p-process nucleosynthesis show how sensitive the photoneutron stellar reaction rate can be to the experimental data in the vicinity of the neutron threshold.

Speaker: Adriana Banu (James Madison University, Department of Physics and Astronomy, Harrisonburg, Virginia 22807, USA)

ANPC2019-ABanu.pdf

16:00 → 18:00 Session 4

18:00 → 18:15 Experimental study with light RIB at ACCULINNA-2

An important upgrade of the Flerov Laboratory of Nuclear Reactions Radioactive Ion Beam facility at JINR is start of the operation of a new high acceptance device called ACCULINNA-2. An overview of the design, construction and commissioning studies of the ACCULINNA-2 separator are presented. The separator will be equipped with a modern cryogenic tritium target cell, with zero degree spectrometer including a neutron detector array, and the TPC detector. This opens a wide range of experimental possibilities. Preliminary results of the experimental study of $^6$He + d scattering and search for the $^7$H nucleus are presented. An overview of light radioactive ion beams experimental program is given.

Speaker: Dr Grzegorz Kaminski (FLNR, JINR)

Grzegorz Kaminski ANCP 2019.pdf