Coincidence summing correction factors for 238U and 232Th decay series using the Monte Carlo method

[EN] Environmental samples analyzed in gamma spectrometry laboratories usually contain natural radionuclides such as 238U and 232Th. Using gamma spectrometry techniques is possible to estimate the activity of these radionuclides by measuring the gamma emissions of radionuclides belonging to their decay chain. Nonetheless, some of these radionuclides emit photons in cascade presenting Coincidence Summing (CS), which if not corrected, may affect the final activity quantification. The aim of this work is to apply the Monte Carlo method to calculate the True Summing Correction Factors (TSCFs) for 238U and 232Th decay series for different sample configurations (geometry and matrix) using the GEANT4 toolkit. In order to validate the results provided by GEANT4 using the RDM, the software TRUECOINC has been applied to calculate also the TSCFs. In addition, the influence of the geometry/matrix on the TSCFs is analyzed. The authors gratefully acknowledge financial support from the Catedra CSN-UPV Vicente Serradell, Spain as well as the Laboratorio de Radiactividad Ambiental (Universitat Politecnica de Valencia), Spain for the dedicated funding and resources to this research work under Grant no. FPI-2015-S2-1576 Ordóñez-Ródenas, J.; Gallardo Bermell, S.; Ortiz Moragón, J.; Martorell Alsina, SS. (2019). Coincidence summing correction factors for 238U and 232Th decay series using the Monte Carlo method. Radiation Physics and Chemistry. 155:244-247. https://doi.org/10.1016/j.radphyschem.2018.09.013 Agostinelli, S., Allison, J., Amako, K., Apostolakis, J., Araujo, H., Arce, P., … Barrand, G. (2003). Geant4—a simulation toolkit. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 506(3), 250-303. doi:10.1016/s0168-9002(03)01368-8 Debertin, K., & Schötzig, U. (1979). Coincidence summing corrections in Ge(Li)-spectrometry at low source-to-detector distances. Nuclear Instruments and Methods, 158, 471-477. doi:10.1016/s0029-554x(79)94845-6 Décombaz, M., Gostely, J.-J., & Laedermann, J.-P. (1992). Coincidence-summing corrections for extended sources in gamma-ray spectrometry using Monte Carlo simulation. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 312(1-2), 152-159. doi:10.1016/0168-9002(92)90146-u Dryák, P., & Kovář, P. (2009). Table for true summation effect in gamma-ray spectrometry. Journal of Radioanalytical and Nu