Coincidence Summing Corrections in Gamma-Ray Spectrometry Using GEANT4 Code

In this paper coincidence summing corrections in gamma-ray spectrometry have been analyzed in depth. Experimental setup included a n-type germanium detector and two efficient geometries of measurement (Marinelli beaker and air filter) calibrated with multi gamma radionuclides in the energy range of 40-1500 keV. Monte Carlo simulations were carried out using the GEANT4 code in order to develop this work. Firstly an optimization of the detector dimensions was performed to obtain the full-energy peak efficiency curve. Next, the simulation of the decay schemes for involved multi gamma radionuclides were appended to the GEANT4 code including beta, alpha, EC decay, together with the subsequent relaxation process consisting of a cascade of fluorescent X-rays and Auger electrons. In order to test the simulations an comparison between an experimental and a calculated spectra of ¹³³Ba point source was carried out. Finally coincidence summing effects for gamma-ray emission and X-ray, Auger electron, beta and EC electron were studied in detail.