HAND-HELD PERSONNEL AND VEHICLE MONITOR

The Energy Research and Development Agency has become increasingly concerned with prevention of the diversion of special nuclear materials (SNM). To deal with this problem, regulations are now in effect which require, among other things, the search of all vehicles and personnel leaving areas containing significant amounts of SNM. Because these searches are specifically for SNM, a radiation detecting doorway monitor through which all outgoing personnel pass can be used instead of a time-consuming physical search. These monitors can handle a large number of passages per hour. However, if the traffic is low, a guard with a hand-held monitor can perform equivalent searches and reduce equipment costs from approximately $10,000 for a doorway monitor to about $750 for a hand-held search instrument. Even greater savings in equipment costs can be had by using the hand-held monitor for vehicles, because a gateway monitor similar to the doorway monitor would require a much larger detector array. This follows from the fact that the source-detector distances will be much larger than those for the doorway monitor.