Investigation of a fibre-coupled beryllium oxide (BeO) ceramic luminescence dosimetry system

The purpose of this study is to investigate the potential use of a beryllium oxide (BeO) ceramic as a radioluminescence (RL) and optically stimulated luminescence (OSL) probe material for fibre-coupled luminescence dosimetry. A portable dosimetry system, named RL/OSL BeO FOD was developed, consisting of a 1 mm diameter, 1 mm long BeO ceramic cylinder coupled to a silica/silica optical fibre. The reader measures the RL signal and also uses a 450 nm laser diode to stimulate the BeO ceramic. A second background optical fibre is used to remove the stem effect. The RL/OSL BeO FOD was characterised in a solid water phantom, using a 6 MV x-ray beam. The RL was found to be reproducible and have a linear response to doses ranging from 30 cGy–15 Gy and dose rates from 100 cGy/min – 600 cGy/min. The OSL response was linear to doses of 10 Gy, becoming supralinear at higher doses. Measured percentage depth curves using the RL/OSL BeO FOD agreed with those measured using an IC15 ion chamber to within 5%, beyond the build up region. It was also found that the RL from BeO ceramic is unaffected by the delivered dose to the probe and hence, it remains constant for a given dose-rate. The insensitivity of the RL to accumulated dose makes BeO ceramic potentially capable of accurate dose-rate measurements without any corrections for the accumulated dose. This study demonstrates the feasibility of BeO ceramic as a versatile fibre-coupled luminescence dosimeter probe. - Highlights: • A fibre-coupled Beryllium oxide (BeO) ceramic dosimeter was developed, named RL/OSL BeO FOD. • The RL/OSL BeO FOD is capable of real-time RL measurements and post exposure OSL measurements. • 6 MV PDD found to be within 5% agreement with Ion chamber measurements. • The RL is shown to be insensitive to the accumulated dose