CASCADES: An Ultra-Low-Background Germanium Crystal Array at Pacific Northwest National Laboratory
State-of-the-art treaty verification techniques, environmental surveillance, and physics experiments require increased sensitivity for detecting and quantifying radionuclides of interest. This can be accomplished with new detector designs that establish high detection efficiency and reduced instrument backgrounds. Current research is producing an intrinsic germanium (HPGe) array designed for high detection efficiency, ultra-low-background performance, and sensitive {gamma}-{gamma} coincidence detection. The system design is optimized to accommodate filter paper samples, e.g., samples collected by the Radionuclide Aerosol Sampler/Analyzer. The system will provide high sensitivity for weak collections on atmospheric filter samples (e.g., < 10{sup 5} fissions), as well as offering the potential to gather additional information from higher activity filters using gamma cascade coincidence detection. The first of two HPGe crystal arrays in ultra-low-background vacuum cryostats has been assembled, with the second in progress. Traditional methods for constructing ultra-low-background detectors were followed, including use of materials known to be low in radioactive contaminants, use of ultra-pure reagents, and clean room assembly. The cryostat is constructed mainly from copper electroformed into near-final geometry at Pacific Northwest National Laboratory. Details of the detector assembly and initial background and spectroscopic measurement results are presented; also a description of the custom analysis package used by this project is given.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1043137
- Report Number(s):
- PNNL-SA-81237; NN2003000; TRN: US1203007
- Resource Relation:
- Conference: AIP Conference Proceedings: Applications of Nuclear Techniques: Eleventh International Conference, June12-18, 2011, Crete, Greece., 1412:208-215
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
AEROSOLS
CLEAN ROOMS
COPPER
CRYOSTATS
DESIGN
DETECTION
EFFICIENCY
GAMMA CASCADES
GEOMETRY
GERMANIUM
PERFORMANCE
PHYSICS
RADIOISOTOPES
SENSITIVITY
VERIFICATION
gamma spectroscopy
coincidence
low background
HPGe
germanium
under-ground measurements