Comparison of simulated and experimental values of self-absorption correction factors for a fast and credible adjust in efficiency curve of gamma spectroscopy

J M Lopes; M P C Medeiros; R W D Garcêz; R A Filgueiras; J L Thalhofer; W F R Silva Júnior; A X Silva

doi:10.1016/j.apradiso.2018.05.005

Comparison of simulated and experimental values of self-absorption correction factors for a fast and credible adjust in efficiency curve of gamma spectroscopy

Appl Radiat Isot. 2018 Nov:141:241-245. doi: 10.1016/j.apradiso.2018.05.005. Epub 2018 May 5.

Authors

J M Lopes¹, M P C Medeiros², R W D Garcêz³, R A Filgueiras³, J L Thalhofer³, W F R Silva Júnior⁴, A X Silva⁵

Affiliations

¹ Nuclear Engineering Program, Federal University of Rio de Janeiro, Av. Horácio Macedo, 2030 - CT, Fundão, 21945-970 Rio de Janeiro, RJ, Brazil. Electronic address: marqueslopez@yahoo.com.br.
² Nuclear Engineering Program, Federal University of Rio de Janeiro, Av. Horácio Macedo, 2030 - CT, Fundão, 21945-970 Rio de Janeiro, RJ, Brazil; Engineering Military Institute, Nuclear Engineering Department, Praça General Tibúrcio, 80, Urca, 22290-270 Rio de Janeiro, RJ, Brazil.
³ Nuclear Engineering Program, Federal University of Rio de Janeiro, Av. Horácio Macedo, 2030 - CT, Fundão, 21945-970 Rio de Janeiro, RJ, Brazil.
⁴ Engineering Military Institute, Nuclear Engineering Department, Praça General Tibúrcio, 80, Urca, 22290-270 Rio de Janeiro, RJ, Brazil; State University of Rio de Janeiro, Structures and Foundations Department, R. São Francisco Xavier, 524, Maracanã, 20550-900 Rio de Janeiro, RJ, Brazil.
⁵ Nuclear Engineering Program, Federal University of Rio de Janeiro, Av. Horácio Macedo, 2030 - CT, Fundão, 21945-970 Rio de Janeiro, RJ, Brazil; Federal University of Rio de Janeiro, Polytechnic College, Av. Athos da Silveira Ramos, 149 - CT, Fundão, 21941-909 Rio de Janeiro, RJ, Brazil.

PMID: 29759888
DOI: 10.1016/j.apradiso.2018.05.005

Abstract

Self-absorption correction factors are fundamental in spectroscopy to correct the efficiency of the samples detection whose density is different from the radioactive standard. Mathematical simulations have been widespread as a tool to facilitate the procedure of correction factors calculation. In this paper, LabSOCS was used to calculate the self-absorption correction factor for some geometries and the values found were compared to those obtained in MCNP and experimental values. The percentage deviations found for the self-absorption correction factor calculated by LabSOCS were below 1.6% when compared to experimental values. Deviations were below 1.9% in the curve extrapolation of the experimental procedure found in literature. Results obtained show that the deviations increase proportionally to the difference between the density values of the radioactive standard and the sample. High percentage deviations were also noticed in simulations whose samples had high densities, complex geometries and low energy gamma-rays.

Keywords: Gamma spectroscopy; LabSOCS; MCNPX; Self-absorption.