A. N. Ismailova | Searcharxiv

arXiv2026

Role of the pre-equilibrium particle emission in the $^{249-251}$No production in the $^{204}$Pb($^{48}$Ca, xn)$^{252-x}$No reaction

Experimental data on the production of $^{250}$No in its ground and isomeric states in the $^{204}$Pb($^{48}$Ca,2n)$^{250}$No reaction at $^{48}$Ca beam energies from 200 to 240 MeV are analyzed within a unified approach combining the Hauser--Feshbach statistical model and the Griffin exciton model, assuming the emission of one pre-equilibrium particle. The influence of pre-equilibrium processes on the production cross sections of the $^{249-251}$No isotopes is investigated. The inclusion of pre-equilibrium light-particle emission significantly improves the description of the measured production cross sections, particularly in the high-energy region, where differences of several orders of magnitude are obtained, and for the population of the ground and isomeric states of $^{250}$No. The proposed approach also reproduces the observed incident-energy dependence of the residual-nucleus production cross sections.

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arXiv2024

Model for the Glauber-type calculations of beam fragmentation at low energies

In the present paper momentum distributions of nuclei produced in the heavy ion beam fragmentation at the relatively low energies (below 100 $A\cdot$MeV) are studied. For this study, a new theoretical approach is developed on the basis of the Glauber model modified for taking into account the energy and momentum conservation laws. In this approach, the longitudinal momentum of the most neutron rich nuclei, $^{10}$Be, $^9$Li, $^8$He, produced in a few neutron removal reactions in the $^{11}$B fragmentation in the Be target at a beam energy of 35 $A\cdot$MeV are calculated. The region of applicability of the new approach is discussed. This approach gives the asymmetric longitudinal momentum distributions at low energies, and the asymmetry is defined by the kinematical locus and geometry of the reaction (central of peripheral reactions). We analyze the changes of the phase volume and the longitudinal momentum distributions with the beam energy and number of the removed nucleons. The results of the calculations are compared to the parametrizations widely used for estimates of nuclear production in fragmentation for planning of nuclear experiments.

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