A semi-emperical formula for the expression of TL fading of natural dolerite

Abstract

The TL fading trend of natural dolerite samples obtained from Abeokuta in South Western Nigeria for varying post annealing irradiation doses and varying post irradiation storage times prior to readout has been investigated with a view of establishing a semi-empirical formula that best describes this phenomenon in this natural rock. The measurements indicate room temperature fading (25-27 oC) of averagely 8% for the first 1 week then a further 3% in the following week followed by saturation for the next 1 month. A general TL response (TL)D of the phosphor (dolerite) irradiated to any gamma radiation dose D (Gy) was obtained as (TL)D = AT -b. A, is an integer which is constant for a particular gamma irradiation dose regardless of the post irradiation storage period T in days before the readout while the exponential b is the specific negative index of T.

Ife Journal of Science Vol. 8 (2) 2006: pp. 127-130