Angular dependence of response of dosimeters exposed to an extended radioactive source

• We investigate the exposer angle dependence of dosimeter response to a gamma source.
• Analytical and Monte Carlo analyses show no angular dependence as claimed by others.
• We derive the dose rate formulae taking into account the path length of photons.
• Analytical and Monte Carlo models have been validated using experimental data.

This study was carried out to investigate the exposure angular dependence of dosimeters response when exposed to the extended gamma source of an irradiation facility. Using analytical and Monte Carlo analysis, we show that dosimeters response has no angular dependence as claimed by a previous study. The dose rate formula we derived takes into account the path length of the photons in the dosimeter. Experimental data have been used to validate our analytical and Monte Carlo methods. Furthermore, the effects on the dosimeters responses in relation to their sizes response of their size and geometry and orientation have been investigated and, within statistical errors, no angular dependence was found.