Development of a Specialized in-Vivo Body Counter for Radiation Monitoring in the Nuclear Industry

摘要

The design, construction, calibration and testing of a prototype mobile counting system to measure natural uranium in the lungs of workers in the nuclear fuel industry is described. The measurement method is based on the detection of gamma rays emitted during the decay of the daughters of uranium. The mobile facility consisted of a shadow shield and phoswich detector system mounted in a medium-sized trunk. Care was taken to ensure undistorted visual and verbal contact between the subject and the operator. Tests were made to optimize the location and thickness of the lead shielding. A single axle truck was insulated and a heater was installed for winter operation. There was sufficient room in the box to include a change room and waiting area as well as the shadow shield and electronics rack. An extensive series of test measurements was made at a number of locations. Control group studies of males were carried out and a model was developed which correctly predicted the subject background in the uranium region of the gamma spectrum when no uranium was present. The mobile counter was calibrated using the Rando Phantom. On a field trip to Bancroft In February 1981 the shadow shield configuration was shown to provide adequate background reduction for accurate uranium-in-lung measurements. With repeated measurements, changes in an individual's lung burden as small as 2 mg. (Atomindex citation 13:661757)