Flerov Laboratory of Nuclear Reactions

Joint Laboratory Seminar

Date and time: Wednesday, 22 October 2025, at 11:00 AM

Venue: Conference Hall, Flerov Laboratory of Nuclear Reactions

1. Seminar topic: “Multi-nucleon transfer reaction studies with velocity filters: progress and prospects”

   Speaker: Haleshappa Devaraja

   Abstract:
   
   Exotic nuclei are typically produced via projectile fragmentation, projectile fission at relativistic energies, or complete fusion reactions at near-Coulomb barrier energies. These production methods, along with the available beam intensities, define the current boundaries of the chart of nuclides. However, theoretical predictions suggest that several thousand additional isotopes may exist on the neutron-rich side, including many along the astrophysical r-process path. Multinucleon transfer (MNT) reactions are considered a potential method to reach certain heavy and superheavy regions of the unexplored chart of nuclides, which is supported by successful experimental results and theoretical calculations. In the recent studies, the authors investigated MNT reactions involving the ⁴⁸Ca+²⁰⁸Pb, ⁵⁰Ti+²⁰⁸Pb, and ⁴⁰Ar+²⁰⁹Bi systems, focusing on the population of nuclei with proton numbers greater than that of the target. The target-like reaction products were separated in flight using the SHELS Velocity Filter of the Flerov Laboratory for Nuclear Reactions, Dubna. The goal was to examine transfer reactions for producing new heavy and superheavy nuclei and assess the applicability of velocity filters for their study. The authors observed and studied about 40 different nuclides, resulting from the transfer of up to eight protons from the projectile to the target and moving in forward direction relative to the beam axis. The speaker will present cross-section systematics for isotopes of elements Z = (83 – 91) measured in experiment and compare them with available data from transfer reactions with actinide targets which lead to isotopes up to Z = 103. The MNT results obtained so far will be discussed, and future prospects for employing MNT reactions to produce new heavy and superheavy isotopes will be presented. In addition, the experimental prospects with the new kinematic separator, the Separator for Transactinide Research (STAR), to be developed at FLNR at JINR, will be briefly discussed, highlighting its advantages for future MNT research. This project will be carried out alongside the modernisation of the U400 Cyclotron (U400R).

2. Seminar topic: “Isospin splitting of giant dipole resonance in medium and heavy nuclei”

   Speaker: Fazilat Rasulova

   Abstract:
   
   В докладе рассматриваются результаты работы в ЛЯР в 2024 г., выполненной в рамках программы JINR Fellowship. Эксперименты проведены на микротроне МТ-25 в диапазоне энергий 10–23 МэВ. Экспериментально полученные выходы фотоядерных реакций на стабильных изотопах natSe, natMo, natCd, natTe и natPt сравнивались с расчетами по TALYS и комбинированной модели фотоядерных реакций (КМФР). Расчеты, выполненные с помощью TALYS, совпадают с экспериментальными данными исключительно для фотонейтронных реакций. В то же время, расчеты, проведенные методом КМФР, демонстрируют хорошее соответствие с экспериментальными данными как для фотонейтронных, так и для фотопротонных реакций. Учет изоспинового расщепления в КМФР позволяет описать экспериментальные данные о реакциях с вылетом протонов. Получены отношения выхода фотопротонов к выходу фотонейтронов для ядер ⁷⁴Se (⁷³As/⁷³Se), ¹⁰⁶Cd (¹⁰⁵Ag/¹⁰⁵Cd), ¹¹⁶Cd (¹¹⁵Ag/¹¹⁵Cd), ¹²⁸Te (¹²⁷Sb/¹²⁷Te) и ¹³⁰Te (¹²⁹Sb/¹²⁹Te). Построены зависимости данного отношения от энергии электронов ускорителя и от протонно-нейтронного соотношения. За исключением результатов по ¹⁰⁶Cd (¹⁰⁵Ag/¹⁰⁵Cd), экспериментальные данные хорошо согласуются с расчетными кривыми, полученными методом КМФР.