Experimental and Simulated Spectral Gamma-Ray Response of a NaI(Tl) Scintillation Detector used in Airborne Gamma-Ray Spectrometry

Abstract. The objective of this work is to simulate the spectral gamma-ray response NaI(Tl) scintillation detectors for airborne spectrometry (AGRS) using state-of-the-art multi-purpose Monte Carlo code FLUKA. study based on a commercial detector system with four individual crystals and total volume 16.8 L. To validate developed model, radiation measurements were conducted 57Co, 60Co, 88Y, 109Cd, 133Ba, 137Cs 152Eu calibration point sources known activities source-detector geometries under laboratory conditions. In addition, empirical resolution functions derived from these combined additional adopting natural uranium, thorium potassium sources. simulation results show superior accuracy precision compared previous AGRS models median relative error < 10 % most Moreover, implementation lower level discriminator model detailed modelling result in significant improvement energies 100 keV studies. Yet thorough statistical analysis incorporating systematic uncertainty estimates revealed statistically deviations between simulated measured spectra region around Compton edge, which could be attributed scintillator non-proportionality. These findings imply that linear energy deposition applied previously should revised considered replaced by more accurate non-proportional models.