Fission rate determination in delayed neutron emission measurements with T(p,n) and D(d,n) neutrons

摘要

A method for accurate measurement of the fission rate in the samples irradiated by neutrons from the T(p,n)(sup 3) He and D(d,n)(sup 3) He reactions is described. The method is based on the measurements of the fission rate in two fission chambers placed in the vicinity of the sample and Monte-Carlo calculations of fission rates in the sample and in the chambers' fissionable layers. The Monte-Carlo calculations employ a neutron source procedure taking into account most of the factors influencing on the neutron spectra characteristics in conditions of a real experiment. An experimental procedure developed for testing the proposed method is discussed. The performance of the method is demonstrated by the results obtained in the measurements of the total delayed neutron yields from neutron induced fission of (sup 237)Np and (sup 235) U. (author) 23 refs, 7 figs, 1 tab