NEW RESULTS ON ABSOLUTE MEASUREMENTS OF 252CF PROMPT FISSION NEUTRON SPECTRUM AT THE LOW ENERGY RANGE
Central Research Institute for Physics
P.P. Dyachenko, E.A. Seregina, V.N. Kononov
Institute of Physics and Power Engineering, Obninsk, USSR
Low energy californium neutron spectrum data are determined by use of new, refined neutron detector efficiency values. The efficiency of the neutron detector, that of a 0.95 cm thick NE-912 glass detector, was determined by an independent measurement, where a 0.0835 cm thin glass detector was used as a reference, the efficiency of which was determined by a Monte-Carlo calculation. A new evaluation of the efficiency of the thick neutron detector results some percent changes in data compared with those of the earlier evaluations. The paper contains the new efficiency data for the thick 6Li glass detector and the californium neutron spectrum evaluated by them. This spectrum can be well described by the complex evaporation model spectrum calculated by H. Märten using a β=0.1 anisotropy value.