Application of differential evolution to fitting OSL decay curves

The differential evolution (DE) algorithm and its application to deconvolution of OSL decay curves into first order components is presented. The algorithm is very fast and robust in finding a global minimum in the problem under consideration. Falling into local minima is a typical problem with deterministic fitting methods, like the Levenberg-Marquardt (LM) algorithm. The algorithm was adapted to form a hybrid evolutionary-linear algorithm, HELA. The evolutionary part of the algorithm was applied only to the decay constants (optical detrapping cross-sections) of the exponential components. For given decay constants, the intensities were calculated using a generalised linear regression method and further improvements were introduced to enhance the efficiency of the algorithm. After finding a solution using the HELA algorithm the parameters obtained were fed into the LM algorithm, providing a nearly automatic procedure for fitting OSL decay curves with a sum of exponential components which in turn may prove very useful in estimating absorbed doses for different components.