DESIGN AND OPERATION OF A GAMMA RAY DETECTOR SYSTEM FOR CONFIRMATORY MEASUREMENTS OF LARGE BOXES AND OBJECTS.

This paper describes the design and operation of a gamma-ray detector system used for confirmatory measurements of large boxes, such as the B-25 and SWB. The instrument employs either 2 or 4 shielded and collimated high purity germanium (HPGe) detectors to quantify the radionuclide content of the waste contained in the samples being measured. The sample is weighed on a load cell prior to the measurement. The box mass determines the average density correction. The sample is then moved sequentially into the pre-determined measurement positions. Measurements of the activity of the box or object are made at one or more positions on each side of the box. Preliminary results are presented for measurements with sources in different positions within a representative test matrix. Comparison is made between distributed source and point source analysis of the data. [ABSTRACT FROM AUTHOR]