Monte Carlo simulation studies of detectors used in the measurement of diagnostic x-ray spectra

Abstract

Accurate determination of diagnostic X-ray spectra requires correction of the data for the energy-dependent response of the X-ray detector. The energy response of 3 types of detectors (intrinsic Ge, lithium-drifted silicon and NaI) commonly used in the diagnostic energy range. A Monte Carlo simulation technique was used to compute photopeak efficiencies, escape peak losses and Compton fractions as a function of incident X-ray energy for a variety of detector thicknesses and diameters. Calculated responses were compared with measurements for the Ge and Si(Li) detectors. The measurements using fluorescent X-rays to simulate the calculated monoenergetic beams indicated good agreement between theoretical and experimental approaches. Techniques for correction of measured spectra for the known response of the detector were evaluated.