Noise Dosimeter - 21st-century Devices

21st-century Devices

The next technology breakthrough came when in the 1990s the United Kingdom Department of Trade and Industry awarded a SMART grant to Cirrus Research to design an ultra-miniature dosimeter. It was to be non-intrusive and not to affect the worker's ability to perform their responsibilities. The resulting device (Fig. 3) was a twin channel device able to meet all the requirements of the European Directive and also the market need for data storage. An important design criteria was that the device had to have no internal display nor any controls, so workers would not be tempted to try to 'modify' or affect the readings; instead the acquired data was transmitted and the device was controlled by an infra-red link. Normally, the acquired exposure data from several badges is transferred to a reader unit where it can be read and stored. As well, most manufacturers offer software to transfer the reader's data to a computer where it can be archived and as well put into a database to allow full and complete reports to be generated.

These new devices are split into two groups; those that have no display on the body-worn acquisition unit, and those that include such a display. While it would seem that a display may be advantageous, many professionals regard it as another potential error source as the user may be tempted to put the device near to a noise source. Their motivation is thought to be either to watch the display move or to try to modify the results, but in either case an additional uncertainty has been introduced into the measurement. An advantage of an internal display however, is that if only a single unit is in use, the exposure can be read without external devices.