Ambient dose equivalent monitoring in the vicinity of a nuclear facility with dosemeters based on Geiger-Müller tubes

Area dosemeters, which are used to estimate the effective dose by ambient dose equivalent measurements in the environment, are employed in both official and non-governmental networks. Area environment monitoring dosemeters cover a wide range of portable and/or installed detectors based on various detection mechanisms. Among others, Geiger-Müller tube detectors are most used for this purpose, more frequently so in non-governmental networks. Since these devices can often produce unreliable data, their dosimetry properties need to be thoroughly assessed. Evaluation of dosemeter performance in terms of response to influence quantity variation in laboratory conditions and on-site via a comparison and a long-term measurement campaign in the vicinity of a nuclear facility was done. A wide range of photon energies from 33 keV up to 1.25 MeV, angles of incidence up to ±90°, and dose rates in the range from near-background level fluctuations to high dose rates were examined under laboratory conditions. In addition to the on-site comparison with a reference instrument a measurement uncertainty budget was estimated for operational measurements in the environmental monitoring applications.