Calculation of the ambient dose equivalent H*(10) from gamma-ray spectra obtained with scintillation detectors

Abstract

The measurement of the ambient dose equivalent H*(10) with automatic real-time radioactivity monitors using gamma-ray spectrometry provides valuable information at short integration times and serves as an alternative to conventional peak analysis of spectra. In this paper, a full methodology for the calculation of this quantity using Monte Carlo (MC) simulations is described and applied to real spectrometric measurements with LaBr₃(Ce) scintillation detectors. The methodology involves the calculation of the fluence-to-H*(10) conversion factors and a method for obtaining the fluence from gamma-ray spectra. The combination of these two elements makes it possible to calculate the H*(10). The obtained results are compared with the H*(10) measurements of a Geiger-Müller (GM) detector. Finally, the necessary activity concentration to produce a certain increment on the H*(10) is discussed for some isotopes. This is used to discuss the analysis capabilities of the spectrometric detectors when compared to GM ones.