EVALUATION OF FISSION NEUTRON MULTIPLICITY DATA FOR Th-232
Bhabha Atomic Research Centre, Bombay - 400 085, India
This paper describes the evaluation of the energy dependent experimental data for the average number of prompt neutrons, <&nu>p, for the neutron induced fission of Th-232 in the energy range from 1 - 20 MeV. The evaluation takes in account not only the actual numerical data of <&nu>p (En) but also certain physical concepts based on the energy balance in nuclear fission. The energy dependence of <&nu>p is represented by two SPLINE fitted curves because of the anomalous behaviour near threshold and multiple chance fission which introduces a non-linear dependence on En. Data are renormalised wherever necessary to the latest recommended value of (3.757) for <&nu>p for spontaneous fission of Cf-252. The present evaluation is compared with the existing ones. Recommended values of <&nu>p (En) are given over the energy range 1 - 20 MeV.
KEYWORDS: Evaluation, Nubar, Th-232, Neutron Fission, En = 1 - 20 MeV, SPLINE fits