Analytic fitting and simulation methods for characteristic X-ray peaks from Si-PIN detector

A semi-empirical detector response function (DRF) model is established to fit characteristic X-ray peaks recorded in Si-PIN spectra, which is mainly composed of four components: a truncated step function, a Gaussian-shaped full-energy peak, a Gaussian-shaped Si escape peak and an exponential tail. A simple but useful statistical distribution-based analytic method (SDA) is proposed to achieve accurate values of standard deviation for characteristic X-ray peaks. And the values of the model parameters except for the standard deviation are obtained by weighted least-squares fitting of the pulse-height spectra from a number of pure-element samples. A Monte Carlo model is also established to simulate the X-ray measurement setup. The simulated flux spectrum can be transformed by Si-PIN detector response function to real pulse height spectrum as studied in this work. Finally, the fitting result for a copper alloy sample was compared with experimental spectra, and the validity of the present method was demonstrated. (authors)