Estimating the terrestrial gamma dose rate by decomposition of the ambient dose equivalent rate

An extensive network of dose rate monitoring stations continuously measures ambient dose rate across Europe, as part of the EURDEP system. Its purpose is early warning in radiological emergencies and documenting its temporal and spatial evolution. In normal conditions, when there is no contribution to the dose rate signal coming from fresh anthropogenic contamination, the data are generated in the background. These background values represent the combined natural radiation and existing anthropogenic contamination (by global and Chernobyl fallout). These data are being stored but have not been evaluated in depth so far, or used for any purpose. In the framework of the EU project ‘European Atlas of Natural Radiation’ the idea has emerged to exploit these data for generating a map of natural terrestrial gamma radiation. This component contributes to the total radiation exposure and knowing its geographical distribution can help establishing local ‘radiation budgets’. A further use could be found in terrestrial dose rate as a proxy of the geogenic radon potential, as both quantities are related by partly the same source, namely uranium content of the ground. In this paper, we describe in detail the composition of the ambient dose equivalent rate, that is the quantity measured by the EURDEP monitors, with respect to its physical nature and to its sources in the environment. We propose and compare methods to recover the terrestrial component from the gross signal. This requires detailed knowledge of detector response. We discuss the matter for the probes used in the Austrian, Belgian and German dose rate networks, which are the respective national networks participating in, and supplying data to EURDEP. It will be shown that although considerable progress has been made in understanding the dose rate signals, there is still space for improvement in terms of modelling and of knowing the model parameters, as condition to accurate decomposition of the dose rate signals. An indispensable condition for success of the endeavour to establish a Europe-wide map of terrestrial dose rate background is progress in harmonising the European dose rate monitoring network.

BOSSEW Peter;  CINELLI Giorgia;  HERNANDEZ CEBALLOS Miguel Angel;  CERNOHLAWEK Nina;  GRUBER Valeria;  DEHANDSCHUTTER Boris;  MENNESON Francois;  BLEHER Martin;  STOHLKER U.;  HELLMANN Ingo;  WEILER F.;  TOLLEFSEN Tore;  TOGNOLI Valerio;  DE CORT Marc; 

2016-12-13

ELSEVIER SCI LTD

JRC98453

0265-931X,   

https://publications.jrc.ec.europa.eu/repository/handle/JRC98453,   

10.1016/j.jenvrad.2016.02.013,