Active Personal Eye Lens Dosimetry With the Hybrid Pixelated Dosepix Detector

lens dosimetry has been an important field of research in the last decade. Dose measurements with a prototype of an active personal eye lens dosemeter based on the Dosepix detector are presented. The personal dose equivalent at 3 mm depth of soft tissue, H-p(3), was measured in the center front of a water-filled cylinder phantom with a height and diameter of 20 cm. The energy dependence of the normalized response is investigated for mean photon energies between 12.4 and 248 keV for continuous reference radiation fields (N-series) according to ISO 4037. The response normalized to N-60 (E = 47.9 keV) at 0 degrees angle of irradiation stays within the approval limits of IEC 61526 for angles of incidence between -75 degrees and +75 degrees. Performance in pulsed photon fields was tested for varying dose rates from 0.1( Sv/h) up to 1000 (Sv/h) and pulse durations from 1 ms up to 10 s. The dose measurement works well within the approval limits (acc. to IEC 61526) up to 1 (Sv/h). No significant influence of the pulse duration on the measured dose is found. Reproducibility measurements yield a coefficient of variation which does not exceed 1% for two tested eye lens dosemeter prototypes.