Position Of Lif:Mg,Cu,P Tl Peak As An Alternative Method For Ultra-High-Dose Dosimetry

LiF:Mg,Cu,P thermoluminescent glow-curve, which shape up to a dose of 1 Gy is remarkably invariable, at higher doses undergoes very strong changes. The most important of them is an occurrence of a new high-temperature peak B, which shows a peculiar property: its position shifts towards higher temperatures with increasing doses. In this work, the possibility of exploiting this shift of peak position for ultra-high-dose dosimetry is studied. The performed investigations, after irradiations with 6 MeV electron doses ranging up to 1.2 MGy confirmed that this property may be indeed successfully used for dosimetry. For doses exceeding about 40 kGy, i.e. for glow-curves for which peak B is well visible, the method based on the simple evaluation of the position of the global maximum of a glow-curve produced very good results. The use of peak position as a measure of the dose makes the proposed method extraordinary resistant to applications at high-temperature conditions. It was found, that it is possible to perform correct measurement of the absorbed dose with detectors subjected before the readout to a pre-heat even up to 350 degrees C.