Order of kinetics for thermoluminescence in LiF TLD-100

Results are presented on the decay of glow peak V (190 degrees C) in powder as well as single crystal chip samples of LiF. The absence of peak IV (170 degrees C) is confirmed and any contribution from higher temperature glow peaks is accounted for, to ascertain that the decay represents the uncontaminated peak V. It is also ascertained that the decrease in TL due to precipitation of impurities does not affect these decay data of comparatively short duration. The order of kinetics is determined by two methods: (i) isothermal decay and (ii) total glow peak. In addition, the applicability of a variable heating rate method is examined for interfering the order of kinetics. It is observed that the variable heating rate method is too insensitive for this purpose. The other two methods give identical values for the order of kinetics (l=1.6). The isothermal decay method is the most sensitive of all the methods. The discrepancy between this result and those of earlier workers is discussed.