Monte Carlo calculation of dose rate conversion factors for in situ gamma spectrometry
Titre du congrès :GEANT4 10th International Conference
Ville du congrès :Bordeaux
Date du congrès :03/11/2005
The use of in situ gamma spectrometry is increasing nowadays thanks to its fast (immediate) results, good detection limits (comparable with laboratory results), and a good representativity of the average of the activity levels over the field under study. The measurement consists in bringing the Ge spectrometer to the field, then from the measured gamma spectra, the specific activity concentrations are derived. In a second step, the kerma rates per isotope are calculated using conversion factors existing in the literature.
Following the directive 96/29/EURATOM, the area monitoring requires the use of the quantity H* (10). However, the corresponding conversion factors necessary for in situ gamma spectrometry do not exist in the literature. In this work, Monte Carlo simulation has been used to infer the spectra of the photon fluence reaching the detector in the in situ gamma spectrometry technique. The conversion factors for H*(10) have been derived. Preliminary results will be presented.