Characteristics of LiF:Mg,Cu,P thermoluminescence at ultra-high dose range

The behaviour of LiF:Mg,Cu,P (MCP-N) detectors at ultra-high doses up to 500 kGy has been investigated. Some very significant changes of the glow-curve shape have been revealed. The most important finding is the appearance of a new peak at exposures above 50 kGy, the position of which shifts toward higher temperatures with increasing dose (from 405 to 470 °C at 500 kGy), in contradiction to standard TL models. The E and s trapping parameters also increase with increasing dose. This new peak appears to have potential application for ultra-high-dose measurements. The TL emission spectrum also changes at such high doses with the appearance of several new bands of wavelengths up to 800 nm.