An efficiency calibration method of segmented gamma scanning in reconstructing radioactive waste drum activity

다국어 초록 (Multilingual Abstract)

For measuring radioactive waste drum, the segmented gamma scanning (SGS) is a quick and efective procedure. The accuracy of reconstructed radioactivity in the drum is directly impacted by SGS efciency matrix. To overcome the challenges of restricted experimental source and excessive workload in existing SGS efciency calibration methods, a new SGS efciency calibration method is presented. The point source efciency function calculates the non-attenuation efciency of each voxel in the calibrated segment. The voxel attenuation efciency is corrected by the linear attenuation coefcient for segments’ absorption. The attenuation efciency for the segment is calculated as the weighted average of all voxel attenuation efciencies in a segment. The waste drum sample is flled with a random mixture of 0.33 g·cm−3 aluminium silicate fbre, 0.64 g·cm−3 wood fbre, 1.84 g·cm−3 polyvinyl chloride plastic and a point source 60Co of 1.244× 105 Bq. The SGS system and the waste drum sample are used to complete SGS experimental measurement, efciency calibration and activity reconstruction. Result shows that the relative deviations of reconstructed activity are − 15.39–30.98% for the extreme case where just a point source 60Co is placed at 16 positions in the drum with diferent heights and eccentric distances. This relative deviation rang of reconstructed activity meets the needs of most users. Compared with other methods which have complicated computational processes, the main beneft of this work is to present a low-performance and easy-to-implement additional alternative to commercial software or existing approaches.