An evaluation of the fast Fourier transform/power spectrum deconvolution method as applied to Doppler-broadened positron annihilation spectra of high-purity aluminium

Abstract

High-purity aluminium samples, thermally treated to systematically vary the concentration of monovacancies or prismatic dislocation loops, were used to evaluate the recently developed fast Fourier transform/power spectrum (FFT/PS) deconvolution method. It is shown that the FFT/PS method is capable of automatically correcting for accidental and/or intentional changes in the instrument resolution function. In addition, the results of this study indicate that both the sensitivity and the accuracy of the energy distribution lineshape parameters are improved by deconvolution. Finally, it is demonstrated that if the filtering error introduced by the FFT/PS procedure is controlled, then it is possible to distinguish aluminium samples containing predominantly vacancy-type defects from those with prismatic dislocation loops as the dominant defect type.