Dual-step thermal treatment for the stability of glow curve structure and the TL sensitivity of the newly developed LiF:Mg,Cu,Si

Several thermal treatments were studied to improve the TL dosimetric characteristics of the newly developed and highly sensitive LiF:Mg,Cu,Si sintered discs. A treatment of 260∘C for 10 min was found to be able to fully restore the TL sensitivity and glow curve structure of the dosimeters which were otherwise altered by heating to 300∘C. A dual-step thermal treatment of 300∘C for 10 min followed by 260∘C for 10 min was found to be optimum and it also minimized the unwanted glow peaks at higher temperatures, thereby reducing the residual TL signal to about 0.025%. For the reuse, annealing treatment of 260∘C for 10 min was found to cause no noticeable change in the TL sensitivity and glow curve structure for 30 cycles of anneal and readout. An effort was also made to understand the role of dual-step thermal treatment in the light of known conversion of Cu+Cu+ and Cu2+Cu2+ and the changes in precipitates and defect complexes involving Mg, Cu, Si, O and OH ions and their dissolution in LiF by heating.