Effect of angular response properties of personal dosemeters on the estimation of effective dose using two dosemeters

Even though the two-dosemeter approach successfully solved the underestimation problem of the single-dosemeter approach for posterior incident radiations, this approach significantly overestimates effective dose for the lateral and overhead beam directions when isotropic-responding dosemeters are used for measurement. This kind of overestimation can be reduced by using anisotropic-responding dosemeters whose responses decrease as the incident angle increases, i.e. from 0 degree (normal incidence) to 90 degrees (lateral incidence). To quantify the reduction of overestimation by using anisotropic-responding dosemeters, this study applied the two-dosemeter approach to several types of anisotropic-responding dosemeters--both ideal and commercial--and then compared the results with those of isotropic-responding dosemeters. This study also derived a set of angular response factors (ARF) which can be used to develop a personal dosemeter with ideal angular response properties for use in the two-dosemeter approach.