Thermoluminescence and electron spin resonance studies of x-irradiated L-alanine:Cr3+ single crystals

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Abstract
Single crystals of x‐irradiated L‐alanine:Cr3+ have been studied between 90 and 300 K by electron spin resonance (ESR) and thermoluminescence (TL) techniques. Ultraviolet (uv) photobleaching of the Cr3+ electron traps and L‐alanine radical centers was also investigated. The results demonstrate that the x‐ray generated radical centers can be destroyed by uv‐induced electron transport activity, and this destruction follows first order kinetics. Also, the transformation of the primary neutral radical species to a secondary radical in L‐alanine was found not to be induced by intermolecular electron transport. The TL glow was determined to proceed by first‐order kinetics at a temperature of 160 K with an activation energy of 0.3 eV and a frequency factor of 1.0×108 s−1. It is suggested that the TL glow may arise from both the decay of the primary cation radical species in L‐alanine and the bleaching of the Cr3+ electron traps, and that the Cr3+ impurity acts to enhance the free radical thermoluminescence.