Evaluation of survey meter responses to the new operational quantities proposed by ICRU Report 95

The International Commission on Radiation Units and Measurements (ICRU) and the International Commission on Radiological Protection have jointly published a report recommending new operational quantities (OQs) for radiological protection. The aim of this study was to investigate the impact of the introduction of this new quantity on the response of 19 commercially available survey meters equipped with geiger mu¨ller tubes and 2 survey meters equipped with ionisation chambers. The energy response was evaluated for x-ray beam qualities defined by International Organization for Standardization (N-30 to N-200). The results strongly depend on model of the survey meter. Some survey meters showed a similar energy dependence for the new ICRU 95 operational quantity<i>H</i>* compared to the current operational quantity<i>H</i>*(10). These survey meters may be adapted to the new OQs requiring only a simple recalibration. However, in some cases, the introduction of the new operational quantity showed the need to physically modify the survey meter by, for example, the introduction of lead filtration.