ELECTRONIC DOSIMETERS - USE IN PERSONAL DOSIMETRY

The traditional technique employed for personal monitoring for regulat ory purposes has been the exposure, reduction and development of photo graphic emulsion. This technique is still the most widely used. During the 1960s other techniques based on other phenomena were developed in cluding radiothermoluminescence, electrets and thermally stimulated ex oelectron emission. More recently solid state detectors, that is semic onductor-based devices have been developed for radiation dosimetry but generally for active, alarm devices, not for regulatory dosemeters. T here have been development programmes in several countries on the appl ication of semiconductor detectors to personal monitoring. These progr ammes are now reaching fruition, aided by the rapid advance in techniq ues of microcircuitry and the reduction in costs of components. The ob vious advantage of active, that is real-time, personal dosemeters is t he immediate indications of dose rates (H(p)(10) and H(p)(0.07)) and t otal doses to date, which can aid ALARA and contribute to the reductio n of total dose and detriment. In addition, such dosemeters can be use d for dose management and dose budgeting purposes. The pressure for re duction in dose limits and for dose constraints has created a requirem ent for dosemeters of lower minimum detectable doses and higher precis ion. The ever present threat of litigation demands that the best avail able and most reliable technology be used. Should electronic personal dosemeters become accepted and approved for use as regulatory dosemete rs, their use is likely to encourage a reconsideration of the complete framework of personal monitoring. An electronic personal dosemeter wi th a long battery life will not need to be returned to approved dosime try services premises other than annually. The regulatory dose informa tion can be extracted remotely under the control of the dosimetry serv ice via a simple reader with modem. For peripatetic workers the doseme ter can be a radiation passport carrying information on the workers ra diation history and ensuring that dose constraints are not exceeded. E ntry into controlled areas can be automatically logged and the dose ma nagement database compiled. The possibility exists of adding a telemet ric capability. Not least, the framework of performance testing and ro utine calibration will need to be reassessed.