Origin of the exponential distribution of traps in glass

A recent rigorous analysis of the broad thermoluminescence (TL) peak of a Brown microcline has shown it to be due to an exponential distribution of traps. Incidentally, from the statistical point of view one expects the traps to follow a Gaussian distribution. In order to elucidate the origin of the exponential trap distribution we have analyzed a set of glow peaks of a light green glass recorded under varying conditions of trap filling. The sample upon gamma -rays irradiation (dose = 7 x 10(3) Gy) exhibits a broad TL peak around 191 degreesC. The broad peak becomes narrower once a thermal cleaning technique is applied to the irradiated specimen. Application of computerized glow curve deconvolution reveals that the broad glow curve is due to the presence of a Gaussian distribution of traps. However, in thermally cleaned glow curves the distribution of traps is found to be exponential. This shows that the exponential distribution of traps results from the deeper tail portion of the Gaussian distribution. (C) 2001 American Institute of Physics.