2005 年 40 巻 3 号 p. 267-276
The authors studied the feasibility of utilizing ebonite as a personal neutron dosemeter in criticality accidents. A disc-shaped ebonite, a hard rubber containing 30wt% sulfur, can be used as a highly effective criticality neutron dosemeter because of a simplicity of measurements of beta activity arising from 32S(n, p)32P reactions. The counting efficiency of beta particles with an end-window GM counter for an ebonite disc in 50mm diameter and 3mm thick was determined by 252Cf neutron irradiation. The neutron spectrum dependency of 32P activity per neutron dose was computed using Monte-Carlo calculations of various neutron spectra that could be encountered in criticality accidents, and the results were tabulated as a set of spectrum correction factors. Performance tests using the SILENE reactor indicated that neutron doses could be evaluated within ±15% with the application of suitable correction factors.