Year
2003
Abstract
The non destructive assay of low density drummed waste by conventional Segmented Gamma-Ray Scanning is a well established and widely used method. In this paper we consider the benefits of analyzing the data gathered using conventional SGS hardware by the Tomographic Gamma Scanning software. The approach still requires that the matrix and activity across a layer is uniform. However, the cross talk between layers can be handled explicitly reducing the need to further assume that layer to nearest layer variations are small when a low aspect ratio collimator is used. Furthermore because the effective (solid angle and matrix attenuation modified) field of view of the detector collimator is properly accounted for the bias introduced by end effects at the bottom and the top of drums is reduced. In other words the matrix correction factor is not calculated for each segment in isolation using a simple formula in terms of the diametrical Transmission, as is the case in the traditional SGS, but as part of a holistic solution.