Extended optical model for fission
A comprehensive formalism to calculate fission cross sections based on the extension of the optical model for fission is presented. It can be used for description of nuclear reactions on actinides featuring multihumped fission barriers with partial absorption in the wells and direct transmission through discrete and continuum fission channels. The formalism describes the gross fluctuations observed in the fission probability due to vibrational resonances, and can be easily implemented in existing statistical reaction model codes. The extended optical model for fission is applied for neutron induced fission crosssection calculations on ^{234,235,238}U and ^{239}Pu targets. A triplehumped fission barrier is used for ^{234,235}U(n,f), while a doublehumped fission barrier is used for ^{238}U(n,f) and ^{239}Pu(n,f) reactions as predicted by theoretical barrier calculations. The impact of partial damping of classII/III states, and of direct transmission through discrete and continuum fission channels, is shown to be critical for a proper description of the measured fission cross sections for ^{234,235,238}U(n,f) reactions. The ^{239}Pu(n,f) reaction can be calculated in the complete damping approximation. Calculated cross sections for ^{235,238}U(n,f) and ^{239}Pu(n,f) reactions agree within 3% with the corresponding cross sections derived within the Neutron Standards leastsquares fit of available experimental data. Lastly, the extended optical modelmore »
 Authors:

^{[1]};
^{[2]};
^{[3]};
^{[2]}
 Univ. of Bucharest, BucharestMagurele (Romania)
 International Atomic Energy Agency, Vienna (Austria)
 Brookhaven National Lab. (BNL), Upton, NY (United States)
 Publication Date:
 Report Number(s):
 BNL1119522016JA
Journal ID: ISSN 24699985; PRVCAN; R&D Project: EST003NEFA; KB0301041
 Grant/Contract Number:
 SC00112704
 Type:
 Accepted Manuscript
 Journal Name:
 Physical Review C
 Additional Journal Information:
 Journal Volume: 93; Journal Issue: 3; Journal ID: ISSN 24699985
 Publisher:
 APS
 Research Org:
 Brookhaven National Laboratory (BNL), Upton, NY (United States)
 Sponsoring Org:
 USDOE Office of Science (SC), Nuclear Physics (NP) (SC26)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 73 NUCLEAR PHYSICS AND RADIATION PHYSICS
 OSTI Identifier:
 1245393
Sin, M., Capote, R., Herman, M. W., and Trkov, A.. Extended optical model for fission. United States: N. p.,
Web. doi:10.1103/PhysRevC.93.034605.
Sin, M., Capote, R., Herman, M. W., & Trkov, A.. Extended optical model for fission. United States. doi:10.1103/PhysRevC.93.034605.
Sin, M., Capote, R., Herman, M. W., and Trkov, A.. 2016.
"Extended optical model for fission". United States.
doi:10.1103/PhysRevC.93.034605. https://www.osti.gov/servlets/purl/1245393.
@article{osti_1245393,
title = {Extended optical model for fission},
author = {Sin, M. and Capote, R. and Herman, M. W. and Trkov, A.},
abstractNote = {A comprehensive formalism to calculate fission cross sections based on the extension of the optical model for fission is presented. It can be used for description of nuclear reactions on actinides featuring multihumped fission barriers with partial absorption in the wells and direct transmission through discrete and continuum fission channels. The formalism describes the gross fluctuations observed in the fission probability due to vibrational resonances, and can be easily implemented in existing statistical reaction model codes. The extended optical model for fission is applied for neutron induced fission crosssection calculations on 234,235,238U and 239Pu targets. A triplehumped fission barrier is used for 234,235U(n,f), while a doublehumped fission barrier is used for 238U(n,f) and 239Pu(n,f) reactions as predicted by theoretical barrier calculations. The impact of partial damping of classII/III states, and of direct transmission through discrete and continuum fission channels, is shown to be critical for a proper description of the measured fission cross sections for 234,235,238U(n,f) reactions. The 239Pu(n,f) reaction can be calculated in the complete damping approximation. Calculated cross sections for 235,238U(n,f) and 239Pu(n,f) reactions agree within 3% with the corresponding cross sections derived within the Neutron Standards leastsquares fit of available experimental data. Lastly, the extended optical model for fission can be used for both theoretical fission studies and nuclear data evaluation.},
doi = {10.1103/PhysRevC.93.034605},
journal = {Physical Review C},
number = 3,
volume = 93,
place = {United States},
year = {2016},
month = {3}
}