Radiation Protection Dosimetry 20:113-116 (1987)
© 1987 Oxford University Press
A Fast Neutron Spectrometer Based on an Electrochemically Etched CR-39 Detector with Degrader and Front Radiator
In addition to having promising applications for the development of a fast-neutron dosemeter, electrochemically etched (ECE) CR-39 detectors also offer the possibility of energy-selective fast-neutron detection. This property stems basically from the fact that, to produce 'sparkable' trails in the polymeric detector subjected to ECE, the charged particle resulting from a neutron interaction must fall within a definite 'energy window'. The lower and upper limits of proton energies that can yield ECE spots in CR-39 have been experimentally determined to be ~50 keV and ~2.2 MeV under our processing conditions. To accomplish our objective, we have developed a technique based on ECE spot-density measurements in CR-39 detectors placed in conjunction with judiciously chosen thicknesses of a polyethylene radiator and a lead degrader. The optimum thicknesses of the radiator and the degrader, for a given neutron energy, are determined by computer calculations.