Measurement and simulation of spectral photon fluence rates in a small building exposed to a 60Co source

Abstract

With the purpose of validating Monte Carlo simulation methods used for the computation of external gamma exposures in urban environments photon fluence rate spectra in a small house exposed to gamma radiation from an external 60Co source have been measured by in situ spectrometry with a portable high purity Ge detector and, on the other hand, calculated by Monte Carlo simulations of the house/environment geometry using two different photon transport codes. An unfolding procedure based on response functions of the detector, calculated by Monte Carlo simulation, was applied to the measured pulse height distributions in order to obtain the photon spectra. The respective photon fluence rate spectra as well as the derived kerma rates obtained are compared for several positions inside and outside of the house. In general a good agreement between measurements and calculations is found, for both the shape as well as the magnitude of the spectra.