Dosimetric properties of an environmental H*(10) dosemeter based on radiophotoluminescence of silver doped phosphate glass

Abstract

The objective of this study was to investigate the energy and angle dependence of the RPL dosimetry system in use at the Paul Scherrer Institute (GBFJ-01 dosimeter, FGD 660 reader, and CDEC-Easy algorithm) for the operational dose quantity H*(10) and compare the results with the requirements from the Swiss dosimetry regulation. The energy response was determined for photon energies between 12 keV (N-15) and 1250 keV (60Co) and the angle response was determined for 65 keV (N-80) and 662 keV (137Cs). The data obtained in this study show that the RPL dosimeters satisfy the requirements of the Swiss dosimetry regulation for the energy dependence, but only partially satisfy the requirements for the angle dependence. For directional irradiations around ±90° the dosimeter response can deviate by more than the 20% allowed by the Swiss dosimetry regulation. If a more realistic testing scenario for the 90° irradiation is used, which includes full rotation of the dosimeter around its reference direction, the response is within 10% of the response at 0° irradiation. Full tests according to the IEC 62387 were not performed and, therefore, performance against this standard cannot be fully evaluated from this data. Nevertheless, the data indicate that the asymmetric dosimeter design would have difficulties satisfying the IEC 62387 standard for H*(10) for low energy photons and large angle irradiation, in spite of the allowance of full rotation for the 90° irradiations.