Cf-252 Spontaneous Fission Neutron Spectrum in the 5-20 MeV Energy Range

摘要

The /sup 252/Cf neutron spectrum has been measured at high energies with a miniature ionization chamber and two different NE213 neutron detectors. The gamma -ray background and the main cosmic background were suppressed by applying an efficient pulse shape n/( gamma , mu ) discrimination. On the basis of the two-dimensional spectroscopy of neutron time-of-flight and scintillation pulse height, the sliding bias method has been used to minimize experimental uncertainties. The experimental data corrected for several systematic influences confirm earlier results which show a trend similar to the NBS evaluation. However, the final spectra obtained for both neutron detectors exhibit negative deviations (up to -10%) from the NBS curve in the 6-12 MeV range. Finally, the experimental results of this work are compared with various statistical-model approaches to the /sup 252/Cf(sf) neutron spectrum. 16 refs, 16 figs, 3 tabs. (Atomindex citation 18:093241)