On the TL traps of KCl crystals

Thermoluminescence (TL) glow curves of KCl crystals irradiated (by X-rays) at the temperatures between 30 and 2500C are presented in this paper. While an extremely poor yield of TL is obtained for these crystals when irradiated at temperatures between 200 and 2350C, the crystals exhibited practically no TL if the temperature of X-irradiation is increased beyond 2400C; no coloration is also noticed in the latter case. The absorption spectrum of the crystals showed prominently in all the cases of irradiation an F band, which is found to get bleached in stages as the flow peaks are removed progressively by heating. From these results it is concluded that even in the case of crystals, colored by X-rays at higher temperatures (< 300C) the TL emission occurs essentially due to the radiative recombination between the released trapped holes (Cl0, Cl020, Cl3- etc.) and the F centers. The significant and new feature of this investigation is that by irradiating the crystals at higher temperatures (< 1800C) it has become possible to isolate the high temperature glow peak at 2960C and thereby calculate the values of the trap depth E (1.182 eV) and the frequency factor S (7.7 x 108/sec). (author)