Characterization of Radiophotoluminescence Dosimeters Under X-Ray Irradiation at High Doses

Abstract

A characterization of radiophotoluminescence (RPL) dosimeters at high doses of X-ray radiation for applications in high radiation areas is presented. Commercial FD-7 silver doped phosphate glasses (1.5 mm x 8.5 mm) in use at CERN for passive dosimetry are irradiated using commercial X-ray tubes. A 1.5 mm thick aluminium filter is used to harden the X-ray spectrum and improve dose homogeneity. Two irradiation campaigns are presented, targeting doses ranging from about 1.3 kGy to 0.46 MGy and dose rates from about 0.6 kGy/h to 6.3 kGy/h, respectively. Monte Carlo simulations performed with PHITS allowed the determination of a factor to convert the dose to water, into the average absorbed dose to RPL material. The found conversion factor is validated by the achieved measurements. The results evidence a satisfactory agreement between the absorbed doses delivered with X-rays and the readout results, based on Co-60 gamma calibration.