The prompt fission neutron spectra for the neutron-induced fission of 235U at En 5 MeV are calculated using nuclear evaporation theory with a semi-empirical model, in which the nonconstant and con- stant temperatures ...The prompt fission neutron spectra for the neutron-induced fission of 235U at En 5 MeV are calculated using nuclear evaporation theory with a semi-empirical model, in which the nonconstant and con- stant temperatures related to the Fermi gas model are taken into account. The calculated prompt fission neutron spectra reproduce the experimental data well. For the n（thermal）＋235 U reaction, the average nuclear temperature of the fission fragment, and the probability distribution of the nuclear temperature, are discussed and compared with the Los Alamos model. The energy carried away by γ rays emitted from each fragment is also obtained and the results are in good agreement with the existing experimental data.展开更多
A measurement of the ^235U prompt fission neutron spectrum (PFNS) by the recoil proton method was performed at the Institute of Nuclear Physics and Chemistry, China. Details of the method, which include the calculatio...A measurement of the ^235U prompt fission neutron spectrum (PFNS) by the recoil proton method was performed at the Institute of Nuclear Physics and Chemistry, China. Details of the method, which include the calculation and validation of the response matrix, are presented. The PFNS for ^235U in the energy range 1–12 MeV, induced by thermal neutrons, was obtained. The measured spectrum in the low-energy region was in good agreement with previous work and the ENDF/B-VII library, except for minor differences. In the high-energy region, however, the relative height of the measured spectrum was greater, and an analysis of the experiment indicated uncertainties of 13% at 10 MeV and 24% at 12 MeV. Experimental results showed that the recoil proton method could be used to measure prompt fission neutron spectra. Some directions for future work are included.展开更多
基金Supported by IAEA-CRP(15905)the State Key Laboratory of Nuclear Physics and Technology,Peking University(SKL-NPT)
文摘The prompt fission neutron spectra for the neutron-induced fission of 235U at En 5 MeV are calculated using nuclear evaporation theory with a semi-empirical model, in which the nonconstant and con- stant temperatures related to the Fermi gas model are taken into account. The calculated prompt fission neutron spectra reproduce the experimental data well. For the n（thermal）＋235 U reaction, the average nuclear temperature of the fission fragment, and the probability distribution of the nuclear temperature, are discussed and compared with the Los Alamos model. The energy carried away by γ rays emitted from each fragment is also obtained and the results are in good agreement with the existing experimental data.
基金supported by the National Natural Science Foundation of China(No.11775196)the Chinese Special Project for ITER(No.2015GB108006)
文摘A measurement of the ^235U prompt fission neutron spectrum (PFNS) by the recoil proton method was performed at the Institute of Nuclear Physics and Chemistry, China. Details of the method, which include the calculation and validation of the response matrix, are presented. The PFNS for ^235U in the energy range 1–12 MeV, induced by thermal neutrons, was obtained. The measured spectrum in the low-energy region was in good agreement with previous work and the ENDF/B-VII library, except for minor differences. In the high-energy region, however, the relative height of the measured spectrum was greater, and an analysis of the experiment indicated uncertainties of 13% at 10 MeV and 24% at 12 MeV. Experimental results showed that the recoil proton method could be used to measure prompt fission neutron spectra. Some directions for future work are included.
