Identification of Shielding Material Configurations Using NMIS Imaging
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
The Nuclear Materials Identification System (NMIS) uses fast neutron tomographic imaging to nonintrusively examine the interior structure of shielded objects. The pixel values in such images represent the attenuation coefficients of the time and directionally tagged fast neutrons from a deuterium-tritium (DT) neutron generator. The reconstruction techniques use either a filtered back projection or a maximum likelihood expectation maximization algorithm. As a first test of the capabilities of these reconstruction techniques to correctly identify individual parts inside of an object, fast neutron imaging was used to identify the regions of shielding surrounding a depleted uranium casting from a library of possible parts. The shielding consisted of multiple regions of common materials such as steel, lead, aluminum, and polyethylene. First, the full object was imaged, and then each of the individual parts was imaged. Several additional parts that were not present in the original object were also imaged to form a library. The individual parts were compared to the full object, and the correct ones were identified using three different methods. These methods included a visual match, an iterative fit of each part, and a mathematical test comparing the sum of squared errors. The successful results demonstrate an initial application of matching. This suggests that it should be possible to implement more sophisticated matching techniques using automated pixel-by-pixel comparison methods in the future.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1023865
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
ALUMINIUM
ATTENUATION
CASTING
DEPLETED URANIUM
Deuterium-Tritium (DT) Neutron Generator
FAST NEUTRONS
IDENTIFICATION SYSTEMS
Imagining
Mathematical Test
Methods
NEUTRON GENERATORS
Neutron Tomographic Imaging
Nuclear Criticality Safety Program (NCSP)
Nuclear Materials Identification System (NMIS)
Reconstruction Techniques
SHIELDING
SHIELDING MATERIALS