Fast Neutron Dosimetry in Nuclear Criticality Accidents
Yook, Chong-Chul;Ro, Seung-Gy;
ABSTRACT
The neutron dosimetrical parameters, i. e., the fission neutron spectrum-averaged cross-sections and the fluence-to-dose conversion factors have been calculated for some threshold detectors with the aid of a computer. The threshold detectors under investigation were the $^{115}In(n,;n')^{115m}In,;^{32}S(n,;p)^{32}P$ and $^{27}Al(n,;{alpha})^{24}Na$ reactions. It is revealed that the average cross-sections($bar{sigma}$) for the $^{32}S(n,;p)^{32}P$ reaction are independent of the spectral functions, namely, the Watt-Cranberg and Maxwellian forms. In the case of the $^{27}Al(n,;{alpha})^{24}Na$ reaction a variation of the $bar{sigma}$ values appears to be highly dependent on the fissioning types. It seems that both the average cross-section for the $^{115}In(n,;n')^{11m}In$ reaction and the conversion factor are insensitive to the spectral deformation of fission neutrons. These phenomena make it applicable to use indium as a possible integral fast neutron dosimeter in nuclear criticality accidents provided that the virgin fission neutrons are completely free from the scattered neutrons.