Multi-nucleon transfer reaction studies with velocity filters: Progress and Prospects/Isospin splitting of giant dipole resonance in medium and heavy nuclei

22.10.2025 – FLNR Scientific Seminar, 11-00, FlerovLab Conference Hall

H.M. Devaraja,

Multi-nucleon transfer reaction studies with velocity filters: Progress and Prospects.
(in connection with the election for the position of s.r.s.)

Exotic nuclei are typically produced via projectile fragmentation or projectile fission at relativistic energies, or through 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, supported by successful experimental results and theoretical calculations, to reach certain heavy and superheavy regions of the unexplored chart of nuclides. In our recent studies, we investigated MNT reactions involving the systems 48Ca+208Pb, 50Ti+208Pb, and 40Ar+209Bi, 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 velocity filter SHELS of the Flerov Laboratory for Nuclear Reactions (FLNR), Dubna. Our goal was to examine transfer reactions for producing new heavy and superheavy nuclei and to assess the applicability of velocity filters for their investigation. We 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. We present cross-section systematics for isotopes of elements Z = (83 – 91) measured in our experiment and compare them with available data from transfer reactions with actinide targets which lead to isotopes up to Z = 103. Our MNT results obtained so far will be discussed, 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, JINR (Dubna), will be briefly discussed, highlighting its advantages for future MNT investigations. This project will be carried out alongside the modernization of the U400 cyclotron (U400R).

Rasulova F.,

Isospin splitting of giant dipole resonance in medium and heavy nuclei.
(JINR fellowship research fellow, first-year report)

The results of work conducted at FLNR in 2024 under the JINR Fellowship program are discussed here. The experiments were performed at MT-25 microtron in the energy range of 10-23 MeV. Experimentally obtained yields of photonuclear reactions on natSe, natMo, natCd, natTe и natPt stable isotopes were compared with TALYS and Combined Photonuclear Reaction Model (CPRM) calculations. Calculations preformed using TALYS coincide with the experimental data only for photoneutron reactions. At the same time calculations preformed using CPRM demonstrate good agreement with the experimental data for both photoneutron and photoproton reactions. Taking isospin splitting into account in CPRM allows one to describe experimental data on reactions with proton emission. Photoproton yield to photoneutron yield ratios were obtained for 74Se (73As/73Se), 106Cd (105Ag/105Cd), 116Cd (115Ag/115Cd), 128Te (127Sb/127Te) and 130Te (129Sb/129Te) nuclei. The dependences of this ratio on the accelerator electron energy and on proton-neutron ratio were plotted. The experimental data, except for the results for 106Cd (105Ag/105Cd), are in good agreement with the calculated curves obtained by CPRM method.

Ф. Расулова
(научный сотрудник-стипендиат jinr fellowship, отчет за первый год)

Изоспиновое расщепление гигантского дипольного резонанса на средних и тяжелых ядрах

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.