1 Scope
The use of a continuous air monitor ( CAM ) is mainly motivated by the need to be alerted quickly and in the most accurate way
possible with an acceptable false alarm rate when a significant activity concentration
value is exceeded, in order to take appropriate measures to reduce exposure of those
involved.
The performance of this CAM does not only depend on the metrological aspect characterized by the decision threshold , the limit of detection and the measurement uncertainties but also on its dynamic
capacity characterized by its response time as well as on the minimum detectable activity concentration corresponding to an acceptable false alarm rate.
The ideal performance is to have a minimum detectable activity concentration as low as possible associated with a very short response time , but unfortunately these two criteria are in opposition. It is therefore important
that the CAM and the choice of the adjustment parameters and the alarm levels be in line with
the radiation protection objectives.
The knowledge of a few factors is needed to interpret the response of a CAM and to select the appropriate CAM type and its operating parameters.
Among those factors, it is important to know the half-lives of the radionuclides involved,
in order to select the appropriate detection system and its associated model of evaluation .
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