Field gamma spectrometry, monte carlo simulations and potential of non-invasive measurements

Abstract

The determination of gamma dose rates is of prior importance in the field of luminescence dating methods. In situ measurements are usually performed by the insertion of dosimeters or a porta-ble gamma spectrometer cell in sediments. In this paper, Monte-Carlo simulations using the GEANT4 toolkit allow the development of a new technique of in-situ gamma dose rate evaluations: A spectrom-eter cell is placed on the surface of sediments under excavation to acquire successive spectra as sedi-ments are removed by excavations. The principle of this non-invasive technique is outlined and its po-tential is discussed, especially in the case of environments in which radioelements are heterogeneous-ly distributed. For such cases, a simple method to reconstruct gamma dose rate values with surface measurements using an attenuator is discussed, and an estimation of errors is given for two simple cases. This technique appears to be applicable, but still needs experimental validation. © 2011 Silesian University of Technology.