Incompatibility of radiation-induced sensitization and re-estimation at low absorbed doses in LiF (TLD-100)

Abstract

The UV/thermal annealing at 300°C for 2 h on 10 3 Gy dosed LiF (TLD-100) phosphor reduced the thermoluminescence intensity of peak 10 by more than a factor of 125, whereas phototransfer-thermoluminescence (PTTL) at room temperature is reduced by a factor of only 26 as compared to the corresponding value in 10 3 Gy dosed and 340°C 30 min dark-annealed sample. The PTTL from UV/thermal annealed sample persisted even after 4 h of bleaching and remained constant at the level of 0.53 equivalent Gy. The ratio of PTTL in peak 5 and peak 7 in UV/thermal annealed sample was 327 as compared to a corresponding ratio of 15.8 for 340°C 30 min dark-annealed sample, thereby indicating the near absence of peak 7 in UV/thermal annealed samples. The response of peak 5 as a function of UV exposure in UV/thermal annealed and dark-annealed LiF (TLD-100) samples increases linearly and supralinearly respectively up to the presently studied UV exposure of 240 min. The difference in the nature of the two PTTL curves appears to show that the centres responsible for the PTTL in UV/thermal bleached samples are different from those related to peak 10.