Neutron dose assessment using an ebonite in criticality accidents

Special techniques are required in criticality accidents to measure the neutron dose, because of the excessively higher dose and the requirement for rapidness for the guidance of the medical services. Activation detectors are the most widely used techniques and the threshold reaction of 32S(n,p)32P has been especially used to provide the information on fast neutrons which are the most important part of criticality accidents. However, the 32P produced by 32S(n,p) reaction is a pure beta particle emitter with a maximum energy of 1.71 MeV and the pretreatment, burning off 32S to leave 32P, is necessary before measurement. This procedure takes longer time and efforts, therefore, more easily measurable techniques have been required. Hence, in order to improve the simplicity of measurement, the feasibility of an ebonite, a hard rubber containing 30% of sulphur, as fast neutron dosemeter was discussed in terms of sensitivity, effective thickness of ebonite, minimum amount of detection, contaminant radionuclide and neutron spectrum dependence. (author)