Accuracy of External Personnel Dosimetry Systems in Mixed Neutron and gamma Radiation Fields

摘要

Estimates of biological effects associated with exposure to external radiation fields are generally based on the measured response of passive personnel dosimetry systems to the incident radiation. The increasing number of persons occupationally exposed to mixed neutron and gamma fields and recent questions concerning the relative biological hazards of different types of radiation have emphasized the need for accurate personnel radiation dose measurements. The performance characteristics of various neutron and gamma personnel dosimetry systems under actual mixed-field conditions have been determined. Analysis of the results indicates that significant inaccuracies can occur in neutron and gamma dose measurements in mixed radiation fields unless dosimeter performance and characteristics of the monitoring environment are considered in dosimeter evaluation. Neutron dose measurement accuracies could be improved by using dosimeters more suited to the anticipated radiation fields, calibrating dosimeters with sources appropriate for the energy spectra to be measured, applying correction factors to account for dosimeter performance in incident radiation fields, and standardizing the basis of reported dose equivalents. With regard to gamma monitoring, intercomparison results indicate that the selection of a basic dosimeter type which is relatively insensitive to neutrons is of great importance for accurate dose measurements in mixed fields. (ERA citation 08:048166)