skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: CASCADES: An Ultra-Low-Background Germanium Crystal Array at Pacific Northwest National Laboratory

Abstract

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.

Authors:
; ; ; ; ; ; ; ; ; ; ; ;  [1]
  1. Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352 (United States)
Publication Date:
OSTI Identifier:
22003917
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1412; Journal Issue: 1; Conference: 11. international conference on applications of nuclear techniques, Crete (Greece), 12-18 Jun 2011; Other Information: (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; AEROSOLS; COINCIDENCE METHODS; CRYOSTATS; CRYSTALS; DESIGN; GAMMA CASCADES; GAMMA DETECTION; HIGH-PURITY GE DETECTORS; NEUTRON SPECTROSCOPY; OPTIMIZATION; PERFORMANCE; SAMPLERS; SENSITIVITY

Citation Formats

Keillor, M. E., Aalseth, C. E., Day, A. R., Erikson, L. E., Fast, J. E., Glasgow, B. D., Hoppe, E. W., Hossbach, T. W., Hyronimus, B. J., Miley, H. S., Myers, A. W., Seifert, A., and Stavenger, T. J. CASCADES: An Ultra-Low-Background Germanium Crystal Array at Pacific Northwest National Laboratory. United States: N. p., 2011. Web. doi:10.1063/1.3665316.
Keillor, M. E., Aalseth, C. E., Day, A. R., Erikson, L. E., Fast, J. E., Glasgow, B. D., Hoppe, E. W., Hossbach, T. W., Hyronimus, B. J., Miley, H. S., Myers, A. W., Seifert, A., & Stavenger, T. J. CASCADES: An Ultra-Low-Background Germanium Crystal Array at Pacific Northwest National Laboratory. United States. doi:10.1063/1.3665316.
Keillor, M. E., Aalseth, C. E., Day, A. R., Erikson, L. E., Fast, J. E., Glasgow, B. D., Hoppe, E. W., Hossbach, T. W., Hyronimus, B. J., Miley, H. S., Myers, A. W., Seifert, A., and Stavenger, T. J. Tue . "CASCADES: An Ultra-Low-Background Germanium Crystal Array at Pacific Northwest National Laboratory". United States. doi:10.1063/1.3665316.
@article{osti_22003917,
title = {CASCADES: An Ultra-Low-Background Germanium Crystal Array at Pacific Northwest National Laboratory},
author = {Keillor, M. E. and Aalseth, C. E. and Day, A. R. and Erikson, L. E. and Fast, J. E. and Glasgow, B. D. and Hoppe, E. W. and Hossbach, T. W. and Hyronimus, B. J. and Miley, H. S. and Myers, A. W. and Seifert, A. and Stavenger, T. J.},
abstractNote = {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.},
doi = {10.1063/1.3665316},
journal = {AIP Conference Proceedings},
number = 1,
volume = 1412,
place = {United States},
year = {Tue Dec 13 00:00:00 EST 2011},
month = {Tue Dec 13 00:00:00 EST 2011}
}
  • 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 tomore » 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.« less
  • ABSTRACT Physics experiments, environmental surveillance, and treaty verification techniques continue to require increased sensitivity for detecting and quantifying radionuclides of interest. This can be done by detecting a greater fraction of gamma emissions from a sample (higher detection efficiency) and reducing instrument backgrounds. A current effort for increased sensitivity in high resolution gamma spectroscopy will produce an intrinsic germanium (HPGe) array designed for high detection efficiency, ultra-low-background performance, and useful coincidence efficiencies. The system design is optimized to accommodate filter paper samples, e.g. samples collected by the Radionuclide Aerosol Sampler/Analyzer (RASA). The system will provide high sensitivity for weak collectionsmore » on atmospheric filter samples, as well as offering the potential to gather additional information from more active filters using gamma cascade coincidence detection. The current effort is constructing an ultra-low-background HPGe crystal array consisting of two vacuum cryostats, each housing a hexagonal array of 7 crystals on the order of 70% relative efficiency per crystal. Traditional methods for constructing ultra-low-background detectors are used, including use of materials known to be low in radioactive contaminants, use of ultra pure reagents, clean room assembly, etc. The cryostat will be constructed mainly from copper electroformed into near-final geometry at PNNL. Details of the detector design, simulation of efficiency and coincidence performance, HPGe crystal testing, and progress on cryostat construction are presented.« less
  • The goal of searching for zero-neutrino double-beta (0{nu}{beta}{beta}) decay is to probe an absolute neutrino mass scale suggested by the mass-splitting parameters observed by neutrino oscillation experiments. Furthermore, observation of 0{nu}{beta}{beta} decay is an explicit instance of Lepton-number non-conservation. A sensitive measurement of two-neutrino double-beta (2{nu}{beta}{beta}) decay can provide critical input to Quasiparticle Random Phase Approximation (QRPA) calculations of the nuclear matrix elements in models similar to those used to extract the absolute neutrino mass from (0{nu}{beta}{beta}) decay experiments. Tellurium-130, an even-even nucleus, can undergo 2{nu}{beta}{beta} decay to the first 0+ excited state of {sup 130}Xe producing three possible {gamma}-raymore » cascades as it transitions to the ground state. The Cascades detector is a high purity germanium (HPGe) crystal array consisting of two ultra-low-background copper cryostats each housing a hexagonal array of seven crystals. The project is currently being developed at Pacific Northwest National Laboratory in Richland, WA (USA), and aims to obtain very high {gamma}-ray detection efficiency while utilizing highly effective and low-background shielding. GEANT4 simulations of the detector are performed for a {sup 130}Te sample in order to determine the optimum size and geometry of the source for maximum detection efficiency and predict its sensitivity for measuring 2{nu}{beta}{beta} decay to the first 0+ excited state of {sup 130}Xe. These simulations are validated with calibration sources and presented.« less
  • This is an introduction to a special issue of the Journal of microbiological Methods based on a recent meeting held at PNNL: the 5th International Symposium on the Interface between Analytical Chemistry and Microbiology.
  • Radiation workers at the Pacific Northwest National Laboratory are divided into two classes based on whether or not they can encounter radioactive contamination in the normal course of their work. Level I workers primarily handle sealed radioactive materials such as those used to calibrate detectors. Level II workers perform benchtop chemistry. The U.S. Department of Energy has strict guidelines on the management of pregnant radiation workers. Staff members may voluntarily notify their line managers of a pregnancy and be subjected to stringent radiation exposure limits for the developing fetus. The staff member and manager develop a plan to limit andmore » monitor radiation dose for the remainder of the pregnancy. Several examples of dose management plans and case examples of the impact of pregnancy on staff member?s technical work and projects will be presented.« less