Low-Mass Bias Issues in Tomographic Gamma Scanning (TGS)
- Robert J.
The term 'low-mass bias' has been used informally in TGS assays to describe systematic errors that arise from zero truncation in the emission image reconstruction. Emission image reconstruction algorithms used in TGS are constrained to give a non-negative result in every image voxel, so repeated assays of samples with low plutonium mass using these algorithms can give results that are high on average. We show that this problem can be avoided by formulating the TGS assay as the total net count rate for the scan times a matrix correction factor derived from the emission image, rather than as the sum of the individual emission image voxel masses. We also show that this formulation is automatically attained in reconstruction algorithms that preserve the total count rate in projections and that any reconstruction algorithm can be forced into this form by a simple normalization of the mass image.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 975632
- Report Number(s):
- LA-UR-01-3764; TRN: US1002515
- Resource Relation:
- Conference: "Submitted to: 42nd Annual Meeting, Institute of Nuclear Materials Management (INMM), Indian Wells, CA, July 15-19, 2001"
- Country of Publication:
- United States
- Language:
- English
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