Analysis of positron annihilation lifetime spectrum by fast Fourier transform (FFT)

This work is the first attempt to decompose the positron annihilation lifetime spectrum into the form of a frequency spectrum by FFT technique. In this method, each real peak in the frequency spectrum indicates a lifetime component, the peak position corresponds to the annihilation constants, and the peak area is proportional to the intensity of the component. The principle of this method was described, and the effects of the instrumental resolution function and the statistical error were taken into account. The analysis results for some simulated spectrum are satisfactory. The advantages of this method are its simplicity, rapidity, less effect of the instrument resolution function and no need to guess what the components are before analysis.