DIFFERENTIAL CROSS SECTIONS FOR GAMMA-RAY PRODUCTION BY 14 MeV NEUTRONS WITH SEVERAL ELEMENTS IN STRUCTURAL MATERIALS
Department of Nuclear Engineering, Osaka University
2-l Yamada-oka, Suita, Osaka 565, Japan
Energy differential cross sections for the gamma-rays produced from the (n,xγ) reactions by 14 MeV neutrons were measured in the gamma-ray energy range from 700 keV to 10 MeV using an NaI spectrometer. Results were obtained for the 8 natural elements; C, Al, Si, Cr, Fe, Ni, Cu and Mo. For prominent discrete gamma-rays in the differential cross sections, the production cross sections were determined by measuring angular distributions with a Ge detector. The gamma-ray energy covered the range between 500 and 3000 keV. The energy distributions have been compared with the differential cross sections evaluated in the nuclear data files of JENDL-3T, ENDL and ENDF/B-IV. The evaluations in JENDL-3T agreed fairly well with the measurements concerning the continuum energy spectra for secondary photons. Discrepancies appeared, however, for Si, Cr and Ni at the energies where the discrete gamma-rays were dominant. The ENDL evaluations were largely deviated from the experimental data. The production cross sections for the discrete gamma-rays in ENDL and ENDF/B-IV were available for the comparison with some of the measured cross sections. Results are presented for C, Al and Si.
KEYWORDS: gamma-ray production, 14 MeV neutron, differential cross section, secondary photon energy distribution, discrete gamma-ray, angular distribution, nuclear data file