A quantitative explanation of low-energy tailing features of Si(Li) and Ge X-ray detectors, using synchrotron radiation

Line shapes have been measured for Si(Li) and Ge detectors using monoenergetic photons in the energy range 1.8–8.3 keV. Accurate escape peak intensities obtained from least-squares-fits to the spectra enable us to provide an improved prescription for the relative intensity of the silicon X-ray escape peak. The shape and intensity of the long-term low-energy shelf are accurately reproduced by a Monte Carlo simulation based upon a simple electron transport model and neglecting diffusion effects. It remains to identify the precise physical origin of the exponential tail close to the peak.