A Comparative Study of Unfolding Techniques for Gamma-Ray Spectra Obtained with NaI(Tl) Scintillation Detectors

Abstract

Iterative unfolding methods are frequently used in acquiring true gamma-ray spectra from the measured spectra. However, the peak resolution of iterative unfolding methods especially, in Gold algorithm method is very challenging, especially in the case of scintillation detectors, where several instrumental artifacts and distortions interfere with the true spectral shape. Therefore, this paper presents a comparative study of the direct matrix inversion unfolding method (DMIUM) and iterative unfolding method with emphasis on the Gold algorithm method (GAM) in converting measured gamma-ray spectra of the NaI(Tl) scintillation detector into the true gamma-ray spectra. The Monte Carlo simulation based on the Geant4 software package was used to study the response function of the NaI(Tl) scintillation detector and for the formation of 200 by 200 response matrices. The results obtained from the number of the integrated photon counts of gamma-ray energies of 662 keV, 1173 keV, and 1333 keV respectively, for the DMIUM were 4, 91, and 93 times greater than in the original energy spectrum while for the GAM method were 3, 14, and 4 times greater than in the original energy spectrum. In conclusion, these results suggest that DMIUM is better in peak resolving ability than the GAM.