Characterization of dose rate instruments for environmental radiation monitoring

Abstract

Abstract Any dose rate instrument used to monitor environmental radiation must be characterized with respect to its response to secondary cosmic radiation and terrestrial radiation. This requires calibrations using different photon radiation fields, the measurement of the instruments internal background and the exposure to secondary cosmic radiation. The methods developed within the cooperation between BfS and PTB are explained in detail by an intercomparison of instruments which are part of the German early warning network IMIS and a high-pressure ionization chamber which was used as the reference instrument. The measurements were performed at the PTB facilities for the dosimetry of environmental radiation. It is shown how the ambient dose equivalent rate of the terrestrial radiation is determined and how the sensitivity of an instrument to a radioactive cloud passing by can be investigated.