PMMA optical fibres for real-time gamma dosimetry

The ability to monitor gamma irradiation in real-time has been demonstrated. The results show a linear response of the radiation-induced attenuation at various wavelengths, agreeable with the Beer-Lambert Law. Due to the intrinsic nature of the PMMA plastic optical fibre, it was possible to monitor the light between 500nm and 680nm. The sensitivity of the fibre to gamma irradiation is shown to be dependant on wavelength, with the sensitivity increasing with decreasing wavelength. With the current system set-up, there is a compromise between sensitivity and dose range, as at wavelengths that have high sensitivities the signal was found to attenuate completely at relatively low doses. At wavelengths between 530nm and 600nm high sensitivity was observed for doses up to 10 kGy. At wavelengths between 600nm and 680nm, the dose range increase to 50 kGy, however the sensitivity is lower.