Determination of the coincidence summing factor by Monte Carlo method using MCNP–CP and PENNUC codes

Abstract

In gamma spectrometry, the quantitative information about the composition of elements present in the experimental samples can be obtained from the efficiency calibration curve, the radioactivity, and the gamma emission intensity of the radioactive. The efficiency of the detector is often affected by the coincidence summing effect. The correction of the coincidence summing factors can be done through the software based on the efficiency transfer method or Monte Carlo simulation. In this study, two Monte Carlo simulation software, MCNP‒CP and PENNUC, were applied to calculate the coincidence summing factors of four radioactive 22Na, 60Co, 133Ba, and 134Cs by the simulation method. The calculated models from the benchmark with two types of detectors of n-type and p-type, using different source geometries such as point source, water, soil, and filter samples, were used. This study aimed to validate the spectral response as well as to compare the coincidence summing factors between MCNP‒CP and PENNUC. The results showed that the coincidence summing factors calculated by two simulation software gave a good agreement with an average relative deviation of less than 2%. The coincidence summing factors calculated by two simulation programs were verified by the statistical T-test with a linear correlation value of rxy = 0.995.