The thermoluminescence of Toshiba FD-1 and FD-7 RPL glass

The thermoluminescent response of Toshiba FD-1 and Toshiba FD-7 radiophotoluminescent dosimetry glass to Co-60 gamma radiation has been studied at doses of up to 66 kGy air kerma and 590 kGy air kerma respectively. The FD-1 glass was in the form of rods 1 mm in diameter by 6 mm long whereas the FD-7 glass was in the form of blocks of 4.6 mm square and 1.47 mm thick. The FD-1 rods had a pre-dose signal equivalent to 180 Gy and were useable up to the maximum dose studied although the response-dose curve was slightly supralinear at low doses. The FD-7 samples had a predose of 6.2 Gy and began to show severe saturation beyond about 1 kGy. The specific TL efficiencies (counts.mg.(-1).Gy(-1)) of the two glass types have been compared with LiF and BeO and found to be some six orders of magnitude lower.