GAMMA QUANTA EMISSION AT INTERACTION OF FAST NEUTRONS WITH 235U, 238U AND 232Th
V.G. Khlopin Radium Institute, Leningrad, USSR
The γ-rays spectra have been measured at interaction of neutrons with 235U, 238U and 232Th. The energies and excitation cross sections of several hundred γ-transitions have been determined at neutron energy 3 MeV. The γ-transitions of the (n, n'γ) reaction have been identified, as well as the transitions belonging to the prompt γ-radiation of fission fragments. The level excitation cross sections in the (n, n'γ) reaction have been obtained for 232Th and 238U. The total cross section of γ-ray production has been also determined. The experimental results have been compared with the results of the statistical model calculation. A good accordance is obtained for the total γ-spectra and, in general, a satisfactory agreement for the level excitation cross sections. Possible reasons are discussed of the discrepancy between the calculated and the measured values of some low-lying states population.
KEYWORDS: γ-rays spectra, 235U, 238U, 232Th, neutron energy 3 MeV, measuring, statistical model calculations