BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CERN//INDICO//EN
BEGIN:VEVENT
SUMMARY:Neutron-induced fission of 232-Th: calculation of the reaction cro
 ss-section
DTSTART;VALUE=DATE-TIME:20261027T162500Z
DTEND;VALUE=DATE-TIME:20261027T163000Z
DTSTAMP;VALUE=DATE-TIME:20261021T015553Z
UID:indico-contribution-6458@cern.ch
DESCRIPTION:Speakers: Aleksey Grigorev ()\nNeutron-induced fission of 232-
 Th: calculation of the reaction cross-section\n\n\nA.K. Grigoriev\n\nNatio
 nal Research Nuclear University MEPhI\, Moscow\, Russia\n\nThis work inves
 tigates the feasibility of reproducing the dependence of the ²³²Th fiss
 ion cross-section on incident neutron energy in the 0.1-40 MeV range using
  the TALYS-2.2 code [1]. This study represents the first stage of a projec
 t aimed at describing the differential fission cross-section - or\, equiva
 lently\, the angular distribution of fission fragments - defined as the ra
 tio of the differential cross-section to the total cross-section (integrat
 ed over all fragment emission\nangles). While the fission cross-section is
  primarily determined by the shape of the fission barrier and the nuclear 
 level density at the barrier\, the angular distribution depends on the dis
 tribution of these states with respect to the projection K of the nuclear 
 spin onto the axis of elongation of the fissioning nucleus (see\, e.g.\, [
 2]) - a characteristic to which the fission cross-section itself is insens
 itive. Insights into the distribution of the quantum number K derived from
  experimental data could accelerate the development of modern approaches t
 o modeling the dynamics of fissioning nuclei with non-zero spin.\n\nThe ²
 ³²Th nucleus is one of the few for which experimental data exist regardi
 ng the energy dependence of not only the neutron-induced fission cross-sec
 tion (see\, e.g.\, [3]) but also the angular anisotropy of fission fragmen
 ts [4\, 5]. Additional interest in the ²³²Th nucleus stems from experim
 ental evidence indicating the existence of a third hump in the fission bar
 rier of the compound nucleus ²³³Th. However\, it has been found that ca
 lculations performed using the TALYS-2.2 code with default parameters yiel
 d an overestimated fission cross-section.\n\nTo refine the description\, t
 he heights and widths of the fission barriers were varied for the compound
  nucleus ²³³Th and for thorium isotopes with mass numbers 232-228\, who
 se fission contributes to the observed total fission cross-section via the
  (n\,1nf)-(n\,5nf) channels. The sensitivity of the fission cross-section 
 to the excited-level density and the shape of the fissioning nuclei at the
  barriers was also investigated. A triple-humped barrier model for ²³³T
 h provides a smooth overall description of the energy dependence of the fi
 ssion cross-section\; however\, a double-humped barrier parameterization y
 ields similar results\, leaving the question of the necessity of a third h
 ump unresolved. The resulting parameter values ​​can serve as a basis 
 for the next stage of the work: calculating the differential cross-section
  for the ²³²Th(n\,f) reaction.\n\n1. A.J. Koning\, S. Hilaire\, S. Gori
 ely. EPJA\, v. 59\, p. 131 (2023).\n2. R. Vandenbosch\, J.R. Huizenga. Nuc
 lear Fission. - New York\, Academic Press\, Inc.\, 1973.\n3. O.A. Shcherba
 kov et al. JNST\, v. 39\, suppl. 2\, p. 230 (2002).\n4. I.V. Ryzhov et al.
  Nucl. Phys. A\, v. 760\, p. 19 (2005).\n5. Vorobyev A.S. et al. JETP Lett
 ers\, v. 102\, p. 203 (2015).\n\nhttps://indico.particle.mephi.ru/event/62
 6/contributions/6458/
LOCATION:Sevastopol hotel Conference Hall 1
URL:https://indico.particle.mephi.ru/event/626/contributions/6458/
END:VEVENT
END:VCALENDAR