Online gamma dose-rate measurements by means of a self-powered gamma detector

Gamma dose-rate profiles have been measured by means of a self-powered gamma detector (SPGD) in a gamma irradiation facility using ⁶⁰Co sources, situated in the side pool of the BR2 materials testing reactor. Because of its small size (diameter of only 4 mm), the SPGD is ideally suited to perform very localized gamma dose-rate measurements. It has been shown that the SPGD can provide precise relative measurements of the local gamma dose rate in the range 0.5-20 kGy/h. A very detailed Monte Carlo code has been developed to relate the gamma dose rate (for a given gamma spectrum) to the current induced by the SPGD. The obtained conversion factor could thus be used to determine the absolute gamma dose rate.