BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CERN//INDICO//EN
BEGIN:VEVENT
SUMMARY:Double-humped fission barrier and statistical mechanism of formati
 on of angular anisotropy of fission fragments
DTSTART;VALUE=DATE-TIME:20241024T071500Z
DTEND;VALUE=DATE-TIME:20241024T073000Z
DTSTAMP;VALUE=DATE-TIME:20260811T210028Z
UID:indico-contribution-4174@cern.ch
DESCRIPTION:Speakers: A. L. Barabanov (National Research Centre “Kurchat
 ov Institute”\, Moscow\, Russia\; National Research Nuclear University M
 EPhI\, Moscow\, Russia)\nFission of heavy nuclei by neutrons at low and in
 termediate energies (up to 100 MeV) occurs at relatively low angular momen
 ta\, which has little effect on the dynamics of nuclear deformation. Due t
 o this\, the anisotropy of the angular distribution of fission fragments r
 elative to the direction of motion of incident neutrons is determined by t
 he distribution over the projection K of the spin of the fissioning nucleu
 s onto the deformation axis. This distribution is formed at the fission ba
 rrier [1\,2]. At sufficiently high excitation energies\, the distribution 
 over quantum number K is determined by statistical mechanism [3] and depen
 ds on the deformation and temperature of the nucleus. However\, due to var
 ious difficulties\, experimental and theoretical studies of the angular an
 isotropy of fission fragments by neutrons have not received sufficient att
 ention for a long time. In particular\, there is a lack of understanding o
 f the role of the  the internal and external humps of fission barrier in t
 he formation of the K-distribution in each fissionable nucleus. Meanwhile\
 , the answer to this question depends on various factors that determine th
 e energy dependence of the nuclear fission cross section for neutrons.\nOv
 er the past decade\, we have conducted measurements on a neutron time-of-f
 light spectrometer based on the GNEIS neutron complex at the 1 GeV proton 
 synchrocyclotron of the National Research Centre “Kurchatov Institute”
  - PNPI (Gatchina) . We have obtained significant data on fission cross se
 ctions and the angular distributions of fission fragments for low and inte
 rmediate energy neutrons. In addition\, we have developed new approaches t
 o the analysis of these characteristics [4\,5]. In this paper\, we demonst
 rate that in the area of ​​applicability of the statistical model\, it
  is possible to determine from the angular distribution of fragments which
  hump of the fission barrier is responsible for the formation of the K-dis
 tribution.\n\n[1] A. Bohr. Proceedings of the International Conference on 
 the Peaceful Uses of Atomic Energy\, 1955. V. 2. United Nations\, New York
 \, 1956. P. 151.\n\n[2] A. L. Barabanov\, W. I. Furman. Z. Phys. A 357\, 4
 11 (1997).\n\n[3] R. Vandenbosch\, J. R. Huizenga. Nuclear Fission. New Yo
 rk\, Academic Press\, Inc.\, 1973.\n\n[4] A. S. Vorobyev et al. Phys. Rev.
  C 108\, 014621 (2023).\n\n[5] A. S. Vorobyev et al. Eur. Phys. J. A 60\, 
 117 (2024).\n\nhttps://indico.particle.mephi.ru/event/436/contributions/41
 74/
LOCATION: Moskvorechye 2
URL:https://indico.particle.mephi.ru/event/436/contributions/4174/
END:VEVENT
END:VCALENDAR