Activity Of EURADOS In Environmental Solid State Dosimetry

Working Group 3 (WG3) of the European Radiation Dosimetry Group (EURADOS) carries out research projects and coordinated activities to advance the scientific understanding of environmental dosimetry and especially to promote the technical development of new methods in environmental monitoring. In this field of dosimetry, the measurement of small additional doses caused by artificial radiation on top of the natural environmental radiation is a challenge. Further, WG3 stimulates the organisation of intercomparison programmes and the definition of standards and recommendations in the field of environmental radiation monitoring (ERM). WG3 has played a significant role in the harmonisation of early warning dosimetry network stations in Europe and has organised 6 EURADOS intercomparison exercises; in which 42 institutions from 19 countries have participated. Today, about 5000 stations provide real-time dose rate data to a database run by the European Commission. Within WG3 a subgroup (S1) on spectrometry system was formed in 2013. Since then, WG3 has been involved in the field of spectrometry systems used both for dosimetric and spectrometric monitoring in the environment. A remarkable result of the WG3 - S1 is that many members contributed to the new European Joint Research Project 'Metrology for radiological early warning networks in Europe' which started in 2014. A second subgroup WG3 - S2 on passive dosimetry in ERM was inaugurated in 2014. To gain an overview of the passive dosimetry practice in ERM, WG3 - S2 decided to collect information by means of a questionnaire which has been send to European dosimetry services. One of the results was the identification of some open questions, problems in ERM (for example terminology, protocol of routine dosimetry, uncertainty assessment) which require clarification for harmonisation of ERM using passive dosimeters. Another result was that there exists a need for intercomparisons. The first intercomparison for passive H*(10) area dosimeters used for ERM (IC2014env) took place from spring to autumn 2014 at (PTB). Dosimeters were exposed at different PTB reference measuring sites to check the home calibration as well as the response of the dosimetry systems to cosmic and terrestrial radiation. 33 dosimetry systems were investigated in total by exposing 16 dosimeters per system under different conditions. Special attention was taken for the transport dose correction. Preliminary results demonstrated that the dosimeter response values were mostly around 1 in a band of ± 20 %, but a pronounced over-response to cosmic radiation has been observed. (author).