Active Personal Eye Lens Dosimetry with the Hybrid Pixelated Dosepix Detector

Abstract

Eye 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, $H_{\text{p}}(3)$, 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 $12.4$keV and $248$keV for continuous reference radiation fields (N-series) according to ISO 4037. The response normalized to N-60 ($\overline{E}=47.9\text{keV}$) at $0^{\circ }$ angle of irradiation stays within the approval limits of IEC 61526 for angles of incidence between $-75^{\circ }$ and $+75^{\circ }$. Performance in pulsed photon fields was tested for varying dose rates from $0.1\frac{\text{Sv}}{\text{h}}$ up to $1000\frac{\text{Sv}}{\text{h}}$ and pulse durations from $1\text{ms}$ up to $10\text{s}$. The dose measurement works well within the approval limits (acc. to IEC 61526) up to $1\frac{\text{Sv}}{\text{h}}$. 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.

This work has been submitted to the IEEE for possible publication. 9 pages, 10 figures