Influence of different types of phantoms on the calibration of dosemeters for eye lens dosimetry

Yoshitomi, Hiroshi   ; Kowatari, Munehiko

Both cylinder and slab phantoms have been recommended for the calibration phantoms for eye lens dosimetry in the |IAEA TECDOC. This study aims to investigate the influence of these phantoms on the calibration of dosemeters for eye lens dosimetry. In order to fulfill the purpose, the backscatters of photons and electrons from practically used water-filled phantoms were evaluated by calculations and experiments. Calculations showed cylinder phantom and slab phantom were found to well-simulate the effect of backscattered photons within 10% and 5%, respectively. It was also found that a cylinder phantom had 10% lower backscattered effect over the range of 50-100 keV. Due to this, the measured calibration factors of cylinder phantom for non-filtered Optically Stimulated Luminescence (OSL) and Radio-Photo Luminescence (RPL) dosemeters increased by 20% and 10%, respectively when compared to the slab phantom. For electrons, no difference was found between cylinder and slab phantoms.