Neutron Nuclear Data Evaluation of Cesium Isotopes for JENDL-4.0

作者：Iwamoto Nobuyuki^*

来源：Journal of Nuclear Science and Technology, 2011, 48(9): 1238-1249.

• cesium
• neutron nuclear data
• fission products
• evaluation
• calculation
• nuclear reaction models
• gamma-ray spectrum
• Maxwellian-averaged cross section
• JENDL-4.0

For the development of JENDL-4.0, neutron nuclear data for fission product nuclides, (133,134,135,136,137)CS, were revised in the incident neutron energy range from 1 eV to 20 MeV by using a coupled-channels optical model (OM), and nuclear reaction models. The OM potential parameters were determined for stable (133)Cs to reproduce the experimental data of total and elastic scattering cross sections and angular distributions of elastically scattered neutrons. The present results reasonably reproduce measured data for (n,2n), (n, p), (n, alpha), and capture reactions on (133)Cs. Important differences between the present results and JENDL-3.3 are found for the capture cross sections of (134,137)CS. The cross section obtained for (137)Cs was smaller than that in JENDL-3.3. This result makes the transmutation of medium-lived (137)Cs increasingly difficult. The production probabilities of metastable states for (134,138)CS via capture reactions on (133,137)CS are compared with experimental values. The present result for (134m)Cs production is marginally consistent with measured data. However, a large discrepancy is recognized for (138m)Cs production. The gamma-ray emission data were evaluated with available measurements, and newly compiled in JENDL-4.0. Maxwellian-averaged capture cross sections were calculated in the energy range from 1 to 10(3) keV, and are compared with other derived data.

• 出版日期2011-9