Effect of Temperature Lag on Trapping Parameters

The effect of temperature lag on the determination of the trapping parameters can be determined using the Randall-Wilkins model for the first-order kinetics [1,2]. The equation of the TL intensity is given by

(1)

with the usual meaning of the symbols and where T ₁, the temperature of the heating element, is given by

Considering the temperature lag, Eq.(1) becomes

(2)

The exponential in Eq.(2) can be developed around the temperature of the maximum TL intensity, T _M, into powers of ( T ₁ ? ? T ? T _M). Thus, Eq.(2) can be approximated, as a first approximation, by

(3)

Comparing Eq.(1) with Eq.(3), it can be observed that, if the temperature lag is ignored, the activation energy and the logarithm of the frequency factor are overestimated by the quantities

According to the experimental results on the peak 4 ^th of TLD-100, errors in E and ln(s) can be of the order of 6% and 3% respectively if the temperature lag is neglected.

Energy Dependence (Procedure)

• prepare n groups (as many points of energy as possible for one intends to use) of at least 6 TLDs each;

• each group of TLDs is inserted in plastic bags and the bags are...