Faculty of Physics University of Warsaw > Events > Seminars > Nuclear Physics Seminar

Nuclear Physics Seminar

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room 1.01, Pasteura 5 at 10:15

mgr Mateusz Fila (ZCOF, IFD, Wydział Fizyki UW)

Investigating photodisintegration reactions with the Warsaw TPC

The determination of the carbon-to-oxygen ratio produced during the final stages of helium burning in stars poses a significant challenge in astrophysics. The thermonuclear reactions that regulate the ratio occur at energies far below the Coulomb barrier, making direct measurements not possible at the relevant energies. Consequently the astrophysical S-factor at the Gamow peak needs to be extrapolated from data at higher energies, which are still very challenging experimentally and affected by large uncertainties. High-intensity γ-ray beams provide a new opportunity to investigate the 12C(α,γ)16O reaction, i.e. the key that regulates carbon-to-oxygen ratios in the Universe, via time-reversal photo-disintegration, offering advantages over previous methods. The Warsaw TPC, an active-target Time Projection Chamber with electronic readout, was developed at the University of Warsaw for comprehensive studies of nuclear reactions with high-intensity γ-ray beams. In 2022, it was deployed at the HIγS facility for measurements focusing on the photo-disintegration of 16O and 12C using monochromatic γ-ray beams. This seminar will cover the detector design, experiment principles and preliminary results.

room 1.01, Pasteura 5 at 10:15

dr hab. Hanna Paulina Zbroszczyk, profesor PW (Politechnika Warszawska)

Strong final state interactions seen by femtoscopy

The study of nucleon-nucleon (N-N), nucleon-hyperon (N-Y), and hyperon-hyperon (Y-Y) interactions are fundamental to understanding the physics of relativistic heavy-ion collisions and neutron stars and the existence of various exotic hadrons. Geometry and dynamics of the particle-emitting source in heavy-ion collisions can be inferred via the femtoscopy method. Two-particle correlations at small relative momentum exploit Quantum Statistics (QS) and the Final State Interactions (FSI), which allow one to study the space-time characteristics of the source of the order of 10^{−15} m and 10^{−23} s. Femtoscopy also enables the investigation of FSI between hadrons, as searches of possible bound states in neutron stars. Baryon measurements and meson ones provide complementary information about source characteristics. This talk will discuss recent femtoscopic results from heavy-ion collision experiments.

room 1.01, Pasteura 5 at 10:15

dr inż. Rafał Lalik (Uniwersytet Jagielloński)

Review of the strangeness physics programme at HADES – past and future perspectives

The aim of HADES is to study various aspects of low-energy QCD. HADES is a versatile spectrometer operating at the SIS18 synchrotron located at the GSI/FAIR in Darmstadt, Germany. It is primarily designed to study dilepton production in proton and heavy-ion induced reactions, but thanks to a recent upgrade, including detector systems for the PANDA and CBM experiments, it has also improved its capability to identify hadrons. This makes it an excellent tool to explore strange hadrons production. The Λ, Σ, Ξ(1321), Λ(1405), Λ(1520), Σ(1385) hyperons, kaons and φ mesons were studied in the few AGeV region providing many interesting results on strangeness production in elementary and heavy ion collisions. In this talk, I will present highlights from former studies of elementary and heavy ion collisions and discuss opportunities emerging from a recent high statistics p+p run at 4.5 GeV.

room 1.01, Pasteura 5 at 10:15

dr Emanuele V. Pagano (INFN - Laboratori Nazionali del Sud, Catania, Italy)

Isospin influence on nuclear reaction dynamics: firsts results on the CHIFAR experiment at LNS and future perspectives about neutron detection

The CHIFAR experiment [1] was carried out at LNS by coupling the CHIMERA multi-detector [2,3] with ten triple telescopes of the novel FARCOS correlator array [4]. The ten telescopes, placed 40 cm far from the target, were arranged in a ring-like structure covering the 15-30° polar angle interval in lab ref. sys. and an azimuthal interval of ≈ 3/2π. Reactions among neutron rich and poor 124Sn, 124Xe, 112Sn beams at 20 AMeV and 64Ni, 64Zn, 58Ni targets were measured. The aim of the experiment is to extend to lower energy the previous studies performed at 35 AMeV [5] on the Intermediate Mass Fragments (IMFs) emission mechanisms and isotopic composition, and on the dependence of the dynamical effects on the isospin content of the entrance channel. In this lecture after a brief introduction to the physic case, the preliminary results of CHIMERA and FARCOS will be presented. Moreover will be also presented the NArCoS (Neutron Array for Correlation Studies) project, a new detector for neutron and light charged particles featuring high angular and energy resolution.

[1] E.V. Pagano et al., Proposal of CHIFAR experiment, approved by the 2017 LNS-PAC.
[2] E. De Filippo and A. Pagano, Eur. Phys. J A50, 32 (2014) and refs. therein;
[3] A. Pagano, Nucl. Phys. News 22, 28 (2012) and refs. therein.
[4] E.V. Pagano et al., EPJ Web Conf. 117, 10008 (2016).
[5] P. Russotto et al., Eur. Phys. J A56, 12 (2020) and refs. therein.

join us at 10:15

Prof. Keung Koo KIM (KINGS, Republic of Korea)

Introduction to SMART

The seminar will concentrate on the development of Small and Medium size Reactors (SMR). The technical barriers and commercial issues will be discussed. The advantages of SMART concept developed in the Republic of Korea will be presented.

Seminar via ZOOM, please contact the organizers to participate.

room 1.01, Pasteura 5 at 10:15

prof. dr Michael Block (GSI and University of Mainz, Niemcy)

Structure of heavy nuclei investigated by laser spectroscopy and mass spectrometry at GSI/SHIP

The investigation of superheavy elements (SHE), i.e., elements with Z > 103, attracts interest from atomic and nuclear physics as well as from chemistry. On the one hand, relativistic effects strongly impact theatomic structure and may alter the chemical properties of these elements compared to their lighter homologues. This manifests, for example, in changes of atomic ground-state configurations and may eventually result in a deviation from the Periodic Table’s structure established by Mendeleev more than 150 years ago. On the other hand, the existence of very heavy and superheavy nuclei is governed by the stabilization due to nuclear shell effects that stabilize them against spontaneous fission. Hence, studies of the evolution of their nuclear structure are of paramount importance. In contrast to nuclei close to stability, where sizeable shell gaps are found for spherical nuclei with magic nucleon numbers, in the heaviest nuclei shell gaps, though smaller ones, also appear for deformed nuclei. This has been established around N = 152 and Z = 100 as well as at N = 162 and Z = 108. In the deformed heavy nuclei also K isomers occur, some which have a longer half-life than the ground state, as has been. Studies of the nuclear structure evolution and the existence of isomers is possible through mass measurements and laser spectroscopy [1, 2]. Mass spectrometry yields binding energies for studies of the shell structure and allows us to identify isomers and to obtain their excitation energy. Laser spectroscopy gives access to changes in mean-square charge radii, the nuclear spin, and electromagnetic moments. Pioneering experiments at the GSI in Darmstadt, Germany utilizing the SHP separator in combination with the SHIPTRAP and the RADRIS setups have recently provided such information for several isotopes of the heavy elements californium to rutherfordium [3-7]. In my presentation I will introduce the basic methods, the employed setups, and review selected recent results.

References
1. M. Block, Nucl. Phys. A 944 (2015) 471.
2. M. Block et al., Prog. Nucl. Phys. 116 (2021) 103834.
3. M. Block, F. Giacoppo, F. Hessberger, S. Raeder, Riv. Nuovo Cim. 45, 279 (2022).
4. M. Laatiaoui et al., Nature. 583 (2016) 495.
5. S. Raeder et al., Phys. Rev. Lett. 120 (2018) 232503.
6. P. Chhetri et al., Phys. Rev. Lett. 120 (2018) 263003.
7. O. Kaleja et al., Phys. Rev. C. 106 (2022) 054325.

room 1.01, Pasteura 5 at 10:15

Dr Irene Dedes (The Henryk Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, Kraków, Poland)

Exotic Shape Systematics in N = 136 Region: Tracing Predicted Molecular Symmetries in Sub-Atomic Physics: Example of Actinides

In the recent years there has been an increasing interest in studies of exotic nuclear shapes and underlying symmetries, the related transition properties and hindrance factors and global structures. In this context it is beneficial to combine the most powerful nuclear structure theories (in our case the mean-field theory) with the powerful mathematical tools to increase the significance of the final result.
Our collaboration combines group-, and group representation theories, inverse problem theory and graph-theory together with phenomenological nuclear mean-field theory in order to predict and study the possible exotic geometrical symmetries on the whole nuclear chart. In the case of the present seminar we will focus on the region of N = 136 isotones and the 4 types of octupole instabilities and implied symmetries.

room 1.01, Pasteura 5 at 10:15

Dr Karolina Kolos McCubbin (Lawrence Livermore National Laboratory, USA)

Nuclear structure and isomer studies in neutron-rich Sb/Sn isotopes

Beta-decay properties like half-lives, decay branching ratios, and isomeric states are key inputs that guide astrophysical nucleosynthesis calculations and fission model. The availability of the nuclear data as well as its accuracy directly impacts the quality of different model predictions. We have performed a number of experiments at the Californium Rare Breeder Upgrade Facility (CARIBU) at Argonne National Laboratory (ANL) to measure some of the important data including nuclear masses and decay properties in the region of doubly magic 132Sn. I will present the results of these studies and plans for the future measurements at ANL and other radioactive ion beam facilities.

room 1.01, Pasteura 5 at 10:15

dr Łukasz Janiak (NCBJ, Świerk)

Pomiar czasu połowicznego zaniku stanu izomerycznego 184Re

Czas połowicznego zaniku jest jednym z podstawowych pojęć fizyki jądrowej. Nowoczesne metody spektroskopii umożliwiają pomiary czasów rozpadu z dużą dokładnością.
Na seminarium przedstawię szczegóły dotyczące eksperymentu w którym mierzony był czas połowicznego zaniku 188-keV stanu izomerycznego w 184Re.

room 1.01, Pasteura 5 at 10:15

dr hab. Michał Kowal (NCBJ, Świerk)

Wybrane problemy syntezy jąder superciężkich

Prawdopodobieństwo syntezy jądra superciężkiego faktoryzujemy na trzy „niezależne od siebie" etapy: wychwyt * fuzja * przetrwanie.
Spojrzę krytycznie na opis każdego z nich.
Na etapie „wychwytu" zwrócę uwagę na zagadnienie deformacji i możliwych różnych orientacji ciężkich jonów w kanale wejściowym.
W szacunkach możliwości przetrwania nowo tworzonego układu superciężkiego omówię rolę bariery rozszczepieniowej, jako parametru kontrolującego to prawdopodobieństwo, oraz gęstość stanów wraz z jego zależnością od energii wzbudzenia i deformacji.
Na etapie formowania mono-nuklearnego tworu przedyskutuję rolę momentu pędu i stochastyczny charakter procesu wzbronienia reakcji fuzji.

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