Low-energy Gamma Unfolding Using NaI(Tl) Geant4 Detector Model and GRAVEL Code

Abstract

In the field of gamma spectrometry with calibrated NaI(Tl) 3” × 3” γ-ray spectrometer, the correction of the photo-peak region of the original spectrum was discussed. In the present paper, GRAVEL algorithm based on Bayes theorem was used to test the unfolding process at low energetic interval, where Compton continium and background contributions are dominant. The simulated response matrix was constructed from mono-energetic γ-ray using validated Geant4 code. The calculated spectrum was compared with experimental ¹³³Ba gamma spectrum. The compared activities were found in good agreement in 4.10 % order.

Keywords: Spectrum unfolding, Gamma-ray spectra, Geant4 simulation, NaI(Tl) detector.

PACS: NaI(Tl): Sodium iodide (NaI) detector activated by thallium (Tl), Geant4: GEometry ANd Traking, FWHM: Full Width at Half Maximum.