Recent Developments of Passive and Active Detectors used in the Monitoring of External Environmental Radiation

The aim of this work is to review some of the latest improvements concerning the different techniques employed for the measurement of external environmental radiation. Nowadays these procedures are an important part of the routine environmental monitoring programmes. Some examples are the radiological surveillance around nuclear and radiation facilities, the operation of early warning networks and the measurement of natural radiation. The progress in passive thermoluminescence dosimetry systems is mainly related to the implementation of tissue equivalent high sensitivity materials such as LiF:Mg,Cu,P. However, the impact of replacing a previous TL system normally based on LiF:Mg,Ti needs to be considered. As an alternative to TLDs, optically stimulated luminescence (OSL) detectors based on Al2O3:C are also becoming important in environmental monitoring. Regarding classical active instruments, the improvements are more focused on the electronics, communications and software advances than on the detectors themselves. As a result, a generation of weatherproof, autonomous and reliable instruments has appeared. The use of portable gamma spectrometry systems and electronic pocket dosemeters provides new approaches to continuous dose rate measurements.