Current Compton Imaging Effort for Homeland Security at LLNL
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1 Current Compton Imaging Effort for Homeland Security at LLNL • Address one of the outstanding problems for Homeland Security: “Faint” sources in the midst of background fluctuations • Gamma-ray imaging to provide Location and shape of nuclear materials Increased sensitivity in the detection of nuclear materials (increase signal-to- background, distinguish threat sources from background fluctuations (spatially and temporarily) • Compton imaging provides high sensitivity with large FOV (4) and w/o heavy collimators • Cryogenically cooled, large-volume Si(Li) + HPGe detector in double-sided strip configuration provide high sensitivity throughout energy range of interest for DHS (180 keV – 2.6 MeV) • Couple 4 Compton imager to 4 visual photo/video camera • Provide 3D imaging either in near field or by moving source or detector 344 keV Imaging of extended 152 Eu source
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Imaging of extended 152 Eu source. 344 keV. Current Compton Imaging Effort for Homeland Security at LLNL. Address one of the outstanding problems for Homeland Security: “Faint” sources in the midst of background fluctuations Gamma-ray imaging to provide - PowerPoint PPT Presentation
Transcript of Current Compton Imaging Effort for Homeland Security at LLNL
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Current Compton Imaging Effort for Homeland Security at LLNL
• Address one of the outstanding problems for Homeland Security: “Faint” sources in the midst of background fluctuations
• Gamma-ray imaging to provide Location and shape of nuclear materials Increased sensitivity in the detection of nuclear materials
(increase signal-to-background, distinguish threat sources from background fluctuations (spatially and temporarily)
• Compton imaging provides high sensitivity with large FOV (4) and w/o heavy collimators
• Cryogenically cooled, large-volume Si(Li) + HPGe detector in double-sided strip configuration provide high sensitivity throughout energy range of interest for DHS (180 keV – 2.6 MeV)
• Couple 4 Compton imager to 4visual photo/video camera
• Provide 3D imaging either in near field or by moving source or detector
344 keV
Imaging of extended 152 Eu source
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Current Compton Imaging effort for Homeland Security at LLNL
• Current Compact Compton Imager
system consisting of 2 Si(Li) and 2
HPGe DSSDs
• 3D position determination by
combining 2D segmentation and
pulse-shape analysis
• 2D and 3D gamma-ray imaging
• Combining 3D gamma-ray and visual
images (LIDAR mapping system)
Si+Ge detectors
Photo camera
Dewar
Pre-amplifiers
20 cm
2D gamma-ray + 3D visual images 3D gamma-ray + 3D visual images
Example of signal shape fitting to deduce #, energies, and 3D position of interactions
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Proposal to DNDO/NSF 07-545 (Academic Research Initiative) to evaluate electron-tracking based Compton imaging
• Reduce cone to arc without loosing angular resolution
• Concept of Si-Drift Detectors
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Examples of measured electron tracks
Position Track
E/dx Vertex (origin of track)Complete vs. incomplete energy deposition
Particle identification?
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Opportunities for UC
• 1m2-scale gamma-ray and neutron detectors and imagers to detect faint sources
• Electron-tracking based imagers, e.g. LAr …
• Gamma-ray imaging …
…. Connection to Biomedical Applications
(10th Campus UCSF…)
