Harmonisation of environmental radiation monitoring: the approach of EURADOS

European co-operation on the measurement of environmental external dose rates has been remarkable in the last twenty years. The experience gained under different European Commission Contracts in the monitoring of the external environmental radiation (gamma and cosmic) has permitted to establish common procedures and get a good degree of harmonization within the participants. In 1994, an EURADOS Working Group (WG) was established with the aim to collect and publish the experience and recommendations on the measurement of external environmental gamma radiation doses. In 1999, the EURADOS WG on Monitoring of External Exposures organised a new intercomparison exercice focused on the instruments that were being employed by different countries in large national networks of radiation detectors (dose rate probes) in order to give early warning of accidents having transboundary implications. The relevance of some conclusions from this exercice motivated the continuity of this WG in the next term (2001-2003) as the WG3 ‘Environmental Radiation Monitoring’. A second intercomparison of dose rate instruments used in the national networks was organized in 2002, for which new facilities and measurements sites were arranged at the PTB Braunschweig. As a novelty, expert teams on the in-situ gamma spectrometry technique also participated in the last exercise.