| Summary: | Measurements are reported on the TL sensitivity (i.e. TL glow output per unit ? ray test dose) of meteoritic specimens as well as terrestrial fluor- and chlor-apatites, as a function of irradiation temperature (T irr ). The irradiation temperatures ranged from liquid nitrogen to room temperature (77 - 293 K). A kilocurie 60Co ? ray source was used to deliver test doses of 400 Gy (40 krad) and 40 Gy (4 krad) to the various samples. A strong dependence of the TL sensitivity upon the temperature of irradiation was noted in the case of Kirin meteorite: its TL sensitivity (for the 493 K readout peak) decreased by a factor of ~2 when T irr rose from liquid nitrogen (77 K) to dry ice in acetone (197 K) temperature, in the case of both 400 Gy and 40 Gy ? ray doses. In the case of the Antarctic meteorite specimen (ALHA 77182,13), there was a smaller effect, viz. a fall of ~14% in the TL output corresponding to dry ice and higher irradiating temperatures as compared to the 77 K irradiation. For chlorapatite, the TL sensitivity decreased monotonically with increasing temperature for both the 563 K and the 448 K glow peaks. For the fluorapatite, the effect of reduced response was observed only between -17 oC (256 K) and room temperature (293 K). Both the theoretical and the practical implications of these observations are discussed.
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