A design study of application of the CsI self-activation method to the neutron rem-counter technique

Abstract

Abstract A design study of application of the CsI self-activation method to the “neutron rem-counter technique” was investigated. A CsI crystal served as both the main target material and 4π counter of neutron activation method in our proposed CsI self-activation method. A commercially available CsI gamma-ray dosimeter was selected as the neutron detector and surrounded with several neutron filters made of polyethylene and silicon rubber containing B4C. The geometric structure of these neutron filters was optimized by a Monte Carlo calculation to make the neutron response similar to the ICRP-74 rem-response. Optimization of this method, the residual sum of squares (RSS) of the calculated neutron response and the ICRP-74 rem-response were minimized by changing the thickness of each filter sequentially. In addition, experimental verification using a Pu–Be source and photoneutrons from a 10 MV-X medical linac has been conducted. From these results, it is concluded that it may be practical for evaluating neutron ambient dose-equivalent simply around medical linacs.