EXFOR-based simultaneous evaluation for fast neutron-induced fission cross section of thorium-232

Abstract

The ${}^{232}$Th neutron-induced fission cross section was evaluated from 500 keV to 200 MeV. The experimental ${}^{232}$Th fission cross sections and their ratios to the ${}^{235,238}$U fission cross sections in the EXFOR library were reviewed and analysed by the least-squares method. The newly published ${}^{232}$Th/${}^{235}$U fission cross section ratios from the time-of-flight measurements at the CERN n_TOF and CSNS Back-n facilities were compiled in EXFOR. Additional simultaneous evaluation was performed by including the experimental ${}^{233,238}$U and ${}^{239,240,241}$Pu fission cross sections and their ratios. The new evaluation provides the ${}^{232}$Th fission cross section systematically lower than the JENDL-5 cross section. The reduction is 4% in the plateau region between 2 and 6 MeV and more significant in the subthreshold fission region. The present evaluation reduces the ${}^{232}$Th fission cross section averaged over the ${}^{252}$Cf spontaneous fission neutron spectrum from the JENDL-5 evaluation by 4%, which is closer to the other general purpose libraries but underestimates Grundl et al's measurement by 11%.

arXiv commentSubmitted to Journal of Nuclear Science and Technology

References in corpus (4)

• Towards a More Complete and Accurate Experimental Nuclear Reaction Data Library (EXFOR): International Collaboration Between Nuclear Reaction Data Centres (NRDC)
• IRDFF-II: A New Neutron Metrology Library
• Measurement of the 235U(n,f) cross section relative to the 6Li(n,t) and 10B(n,alpha) standards from thermal to 170 keV neutron energy range at n_TOF
• EXFOR-based simultaneous evaluation of neutron-induced uranium and plutonium fission cross sections for JENDL-5

Cited by in corpus (2)

• Evaluation of uranium-233 neutron capture cross section in keV region
• EXFOR utility codes (ForEXy) and their application to neutron fission cross section evaluation