Determination of coincidence summing correction factors for ²²na point source

Abstract

The coincidence summing effect plays an important role in HPGe spectrometry, especially at low source-detector distances, due to a large solid angle; therefore, the calculation of correction factors is necessary. The aim of the research described in this paper was to compare values of correction factors for a 22Na point source obtained using the GESPECOR software package (Monte-Carlo method) and experimentally obtained values. Measurements were performed using a semiconductor HPGe spectrometer and the point source axially positioned at nine different distances from the detector end-cap. For the purpose of determining correction factors, a system of equations was formed, which, besides nuclear data as the input parameters, uses the experimentally obtained values of the total count in the entire spectrum, as well as the counts in the full energy peaks. The system of equations was solved for each particular case and correction factors were determined. By comparing the results obtained using the experimental and Monte-Carlo method, it was found that the correction factors for the 22Na point source have discrepancies less than 3%. The significance of these discrepancies was also verified from a statistical point of view using a Student's t-test.