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Title: Background characterization of an ultra-low background liquid scintillation counter

Abstract

The Ultra-Low Background Liquid Scintillation Counter developed by Pacific Northwest National Laboratory will expand the application of liquid scintillation counting by enabling lower detection limits and smaller sample volumes. By reducing the overall count rate of the background environment approximately 2 orders of magnitude below that of commercially available systems, backgrounds on the order of tens of counts per day over an energy range of ~3–3600 keV can be realized. Finally, initial test results of the ULB LSC show promising results for ultra-low background detection with liquid scintillation counting.

Authors:
 [1];  [2];  [2];  [2];  [2];  [2];  [2];  [3];  [2];  [2];  [2];  [2]
  1. Texas A & M Univ., College Station, TX (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  3. Texas A & M Univ., College Station, TX (United States)
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1347962
Report Number(s):
PNNL-SA-120443
Journal ID: ISSN 0969-8043; PII: S0969804316305048
Grant/Contract Number:
AC057601830
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Applied Radiation and Isotopes
Additional Journal Information:
Journal Volume: 126; Journal ID: ISSN 0969-8043
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
07 ISOTOPE AND RADIATION SOURCES; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; low background; liquid scintillation counting; shallow underground laboratory

Citation Formats

Erchinger, J. L., Orrell, John L., Aalseth, C. E., Bernacki, B. E., Douglas, M., Fuller, E. S., Keillor, M. E., Marianno, C. M., Morley, S. M., Mullen, C. A., Panisko, M. E., and Warren, G. A. Background characterization of an ultra-low background liquid scintillation counter. United States: N. p., 2017. Web. doi:10.1016/j.apradiso.2017.01.032.
Erchinger, J. L., Orrell, John L., Aalseth, C. E., Bernacki, B. E., Douglas, M., Fuller, E. S., Keillor, M. E., Marianno, C. M., Morley, S. M., Mullen, C. A., Panisko, M. E., & Warren, G. A. Background characterization of an ultra-low background liquid scintillation counter. United States. doi:10.1016/j.apradiso.2017.01.032.
Erchinger, J. L., Orrell, John L., Aalseth, C. E., Bernacki, B. E., Douglas, M., Fuller, E. S., Keillor, M. E., Marianno, C. M., Morley, S. M., Mullen, C. A., Panisko, M. E., and Warren, G. A. Thu . "Background characterization of an ultra-low background liquid scintillation counter". United States. doi:10.1016/j.apradiso.2017.01.032. https://www.osti.gov/servlets/purl/1347962.
@article{osti_1347962,
title = {Background characterization of an ultra-low background liquid scintillation counter},
author = {Erchinger, J. L. and Orrell, John L. and Aalseth, C. E. and Bernacki, B. E. and Douglas, M. and Fuller, E. S. and Keillor, M. E. and Marianno, C. M. and Morley, S. M. and Mullen, C. A. and Panisko, M. E. and Warren, G. A.},
abstractNote = {The Ultra-Low Background Liquid Scintillation Counter developed by Pacific Northwest National Laboratory will expand the application of liquid scintillation counting by enabling lower detection limits and smaller sample volumes. By reducing the overall count rate of the background environment approximately 2 orders of magnitude below that of commercially available systems, backgrounds on the order of tens of counts per day over an energy range of ~3–3600 keV can be realized. Finally, initial test results of the ULB LSC show promising results for ultra-low background detection with liquid scintillation counting.},
doi = {10.1016/j.apradiso.2017.01.032},
journal = {Applied Radiation and Isotopes},
number = ,
volume = 126,
place = {United States},
year = {Thu Jan 26 00:00:00 EST 2017},
month = {Thu Jan 26 00:00:00 EST 2017}
}

Journal Article:
Free Publicly Available Full Text
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  • The radiological examination of water requires a rapid screening technique that permits the determination of the gross alpha and beta activities of each sample in order to decide if further radiological analyses are necessary. In this work, the use of a low background liquid scintillation system (Quantulus 1220) is proposed to simultaneously determine the gross activities in water samples. Liquid scintillation is compared to more conventional techniques used in most monitoring laboratories. In order to determine the best counting configuration of the system, pulse shape discrimination was optimized for 6 scintillant/vial combinations. It was concluded that the best counting configurationmore » was obtained with the scintillation cocktail Optiphase Hisafe 3 in Zinsser low diffusion vials. The detection limits achieved were 0.012 Bq L{sup -1} and 0.14 Bq L{sup {minus}1} for gross alpha and beta activity respectively, after a 1:10 concentration process by simple evaporation and for a counting time of only 360 min. The proposed technique is rapid, gives spectral information, and is adequate to determine gross activities according to the World Health Organization (WMO) guideline values.« less
  • Pacific Northwest National Laboratory has recently opened a shallow underground laboratory intended for measurement of lowconcentration levels of radioactive isotopes in samples collected from the environment. The development of a low-background liquid scintillation counter is currently underway to further augment the measurement capabilities within this underground laboratory. Liquid scintillation counting is especially useful for measuring charged particle (e.g., B, a) emitting isotopes with no (orvery weak) gamma-ray yields. The combination of high-efficiency detection of charged particle emission in a liquid scintillation cocktail coupled with the low-background environment of an appropriately-designed shield located in a clean underground laboratory provides the opportunitymore » for increased-sensitivity measurements of a range of isotopes. To take advantage of the 35-meter water-equivalent overburden of the underground laboratory, a series of simulations have evaluated the instrumental shield design requirements to assess the possible background rate achievable. This report presents the design and background evaluation for a shallow underground, low background liquid scintillation counter design for sample measurements.« less
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  • ABSTRACT Pacific Northwest National Laboratory (PNNL) has developed an ultra-low-background proportional counter (ULBPC) made of high purity copper. These detectors are part of an ultra-low-background counting system (ULBCS) in the newly constructed shallow underground laboratory at PNNL (at a depth of ~30 meters water-equivalent). To control backgrounds, the current preamplifier electronics are located outside the ULBCS shielding. Thus the signal from the detector travels through ~1 meter of cable and is potentially susceptible to high voltage microdischarge and other sources of electronic noise. Based on initial successful tests, commercial cables and connectors were used for this critical signal path. Subsequentmore » testing across different batches of commercial cables and connectors, however, showed unwanted (but still low) rates of microdischarge noise. To control this noise source, two approaches were pursued: first, to carefully validate cables, connectors, and other commercial components in this critical signal path, making modifications where necessary; second, to develop a custom low-noise, low-background preamplifier that can be integrated with the ULBPC and thus remove most commercial components from the critical signal path. This integrated preamplifier approach is based on the Amptek A250 low-noise charge-integrating preamplifier module. The initial microdischarge signals observed are presented and characterized according to the suspected source. Each of the approaches for mitigation is described, and the results from both are compared with each other and with the original performance seen with commercial cables and connectors.« less