부산대학교 도서관

First measurements characterizing dosimetric properties of a dosimetry system designed for the purpose of active personal dosimetry for photons with mean energies from 12.4 to 1250 keV according to Physikalisch-Technische Bundesanstalt (PTB) requirements are presented. The system consists of three Dosepix detectors, which is a hybrid, pixelated, photon-counting X-ray detector. The energy and angular dependence of the normalized response and the coefficients of variation of the personal dose equivalents $H_{\mathrm{p}}{(10)}$ and $H_{\mathrm{p}}{(0.07)}$ are determined on an International Organization for Standardization (ISO) water slab phantom in continuous reference photon radiation fields according to ISO 4037-1 and ISO 4037-3. The energy response is presented for the narrow spectra N-15 to N-300 and the radiation qualities S-Cs and S-Co for angles of incidence of 0°, 30°, and ±60°. The highest deviation of the response from the reference response is found at N-60, −60° with 1.179 ± 0.007 (standard deviation) for $H_{\mathrm{p}}{(10)}$ . The energy range of use for $H_{\mathrm{p}}{(10)}$ is expected to extend from 12.4 to 1250 keV. For the personal dose equivalent $H_{\mathrm{p}}{(0.07)}$ , the normalized response at ±60° is below the lower limit for N-15, N-20, and N-25. It results in an energy range of use from 24.6 to 1250 keV. The coefficient of variation increases with increasing photon energy and stays below 1% for all measurements.