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Title: Conservation of Isospin in Neutron-rich Fission Fragments

Abstract

On the occasion of the 75{sup th} anniversary of the fission phenomenon, we present a surprisingly simple result which highlights the important role of isospin and its conservation in neutron rich fission fragments. We have analysed the fission fragment mass distribution from two recent heavyion reactions {sup 238}U({sup 18}O,f) and {sup 208}Pb({sup 18}O,f) as well as a thermal neutron fission reaction {sup 245}Cm(n{sup th},f). We find that the conservation of the total isospin explains the overall trend in the observed relative yields of fragment masses in each fission pair partition. The isospin values involved are very large making the effect dramatic. The findings open the way for more precise calculations of fission fragment distributions in heavy nuclei and may have far reaching consequences for the drip line nuclei, HI fusion reactions, and calculation of decay heat in the fission phenomenon.

Authors:
 [1];  [1];  [2];  [1]
  1. Department of Physics, Indian Institute of Technology, Roorkee-247667 (India)
  2. (India)
Publication Date:
OSTI Identifier:
22436701
Resource Type:
Journal Article
Resource Relation:
Journal Name: Nuclear Data Sheets; Journal Volume: 120; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; AFTER-HEAT; CURIUM 245; FISSION FRAGMENTS; HEAVY ION FUSION REACTIONS; ISOSPIN; LEAD 208; MASS DISTRIBUTION; OXYGEN 18; THERMAL NEUTRONS; THERMONUCLEAR REACTIONS; URANIUM 238

Citation Formats

Jain, A.K., Choudhury, D., Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Mumbai-400005, and Maheshwari, B.. Conservation of Isospin in Neutron-rich Fission Fragments. United States: N. p., 2014. Web. doi:10.1016/J.NDS.2014.07.024.
Jain, A.K., Choudhury, D., Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Mumbai-400005, & Maheshwari, B.. Conservation of Isospin in Neutron-rich Fission Fragments. United States. doi:10.1016/J.NDS.2014.07.024.
Jain, A.K., Choudhury, D., Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Mumbai-400005, and Maheshwari, B.. 2014. "Conservation of Isospin in Neutron-rich Fission Fragments". United States. doi:10.1016/J.NDS.2014.07.024.
@article{osti_22436701,
title = {Conservation of Isospin in Neutron-rich Fission Fragments},
author = {Jain, A.K. and Choudhury, D. and Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Mumbai-400005 and Maheshwari, B.},
abstractNote = {On the occasion of the 75{sup th} anniversary of the fission phenomenon, we present a surprisingly simple result which highlights the important role of isospin and its conservation in neutron rich fission fragments. We have analysed the fission fragment mass distribution from two recent heavyion reactions {sup 238}U({sup 18}O,f) and {sup 208}Pb({sup 18}O,f) as well as a thermal neutron fission reaction {sup 245}Cm(n{sup th},f). We find that the conservation of the total isospin explains the overall trend in the observed relative yields of fragment masses in each fission pair partition. The isospin values involved are very large making the effect dramatic. The findings open the way for more precise calculations of fission fragment distributions in heavy nuclei and may have far reaching consequences for the drip line nuclei, HI fusion reactions, and calculation of decay heat in the fission phenomenon.},
doi = {10.1016/J.NDS.2014.07.024},
journal = {Nuclear Data Sheets},
number = ,
volume = 120,
place = {United States},
year = 2014,
month = 6
}
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  • The neutron–proton effective mass splitting in asymmetric nucleonic matter of isospin asymmetry δ and normal density is found to be m* n-p≡(m* n – m* p)/m = (0.41 ± 0.15)δ from analyzing globally 1088 sets of reaction and angular differential cross sections of proton elastic scattering on 130 targets with beam energies from 0.783 MeV to 200 MeV, and 1161 sets of data of neutron elastic scattering on 104 targets with beam energies from 0.05 MeV to 200 MeV within an isospin dependent non-relativistic optical potential model. It sets a useful reference for testing model predictions on the momentum dependencemore » of the nucleon isovector potential necessary for understanding novel structures and reactions of rare isotopes.« less