Change of measured values of area monitoring caused by the transition from 'old' to 'new' measuring quantities

The transition from the quantity 'photon dose equivalent' so far used in area monitoring to the new quantities 'ambient dose equivalent' or 'directional dose equivalent' will in general be accompanied by a discontinuity of measured values. Although such a discontinuity is inevitable it remains nevertheless undesirable. In order to assess the consequences of such a discontinuity estimates on its magnitude are required. Making use of known conversion coefficients and of typical task specific photon fluence spectra an estimate on the magnitude of the discontinuity due to the transition is made for ideal dosemeters, i.e. those with an energy independent response for the perspective quantity of measurement. Additionally the difference in reading of hypothetical dosemeters for the perspective quantity to be measured are analysed for selected model cases. (orig.)