Primary radioactive gas standards (excluding radon)

Unterweger, Michael P.

doi:10.1088/0026-1394/44/4/s10

Cited by 20 publications

(11 citation statements)

References 14 publications

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“…The 17 th issue of a NIST tritiated-water standard, SRM 4927G, was calibrated for 3 with the F2009 solution used in the CCRI(II) key comparison [14]. Table 9 A curious finding of these comparative LS measurements was an apparent 2.6 % discrepancy between the reported values for F1994 and F2009 solutions, which represent the LPRI 1994 standard [11,12] and 2009 measurements by LNHB for a CCRI(II) international comparison [14,20].…”

Section: Discussionmentioning

confidence: 99%

“…Lucas [1] previously summarized the sixteen different tritiated-water standards disseminated by the National Institute of Standards and Technology (NIST), formerly the National Bureau of Standards (NBS), from 1954 to 1999. The most recent of these were standardized by length-compensated internal gas proportional counting [2][3][4]. 3 The procedure for the preparation of tritiated-water standards and the internal proportional gas counting method used at NIST has been described by Unterweger et al [7] and Unterweger and Lucas [8].…”

Section: Historical Overviewmentioning

confidence: 99%

“…One should appreciate that in a log spectrum mode the difference in any two channels (c 2 -c 1 ) or the energy bin width of a single channel is equal to the logarithmic energy ratio log(E 2 /E 1 ). The background-subtracted rates in each channel above the 3 The comparison measurements were conducted by efficiency tracing each of the other solutions against the dilution of SRM 4927F. Each measurement of a SRM 4927F counting source was used to derive a quench-dependent 3 H efficiency as given by (1) where Q is the quench indicating parameter for the measurement, with Q = H# for counter B and…”

Section: Measurement Conditions and Protocolmentioning

confidence: 99%

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Comparison of tritiated-water standards by liquid scintillation for calibration of a new Standard Reference Material®

Collé

Laureano-Pérez

Bergeron

2016

Applied Radiation and Isotopes

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A new National Institute of Standards and Technology (NIST) tritiated-water ((3)H-labeled oxidane) standard was prepared and calibrated. It is the 17th in a series of linked standards since 1954 and will be disseminated as Standard Reference Material® SRM 4927G, having a massic activity of 544.2kBqg(-1), with an expanded (k=2) relative standard uncertainty of 0.96%, at a Reference Time of 1200 EST, 1 May 2015. The calibration is based on relative liquid scintillation (LS) measurements using quench-varied efficiency tracing with two previous 1999 issues, viz., SRM 4927F and 4926E. Measurement comparisons were also made with respect to a 1994 tritiated-water French national standard and to a tritiated-water solution measured by 19 laboratories as part of an international measurement comparison organized by the Bureau International des Poids et Mesures (BIPM) in 2009. Confirmatory measurements for the massic activity of both SRM 4927F and 4927G by a triple-to-double coincidence ratio (TDCR) technique were also made.

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Section: Discussionmentioning

confidence: 99%

Section: Historical Overviewmentioning

confidence: 99%

Section: Measurement Conditions and Protocolmentioning

confidence: 99%

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Comparison of tritiated-water standards by liquid scintillation for calibration of a new Standard Reference Material®

Collé

Laureano-Pérez

Bergeron

2016

Applied Radiation and Isotopes

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“…This efficiency is often driven by the details of the proportional counter design at the ends of the tube where electric fields lines may not produce collectible charge transport with the same proportional gain characteristics as the central portions of the tube. It is possible to use two (or more) separate but "identical" proportional counters to effectively remove any uncertainty related to the ends of the proportional tubes (Unterweger (2007)). In summary explanation, assuming the end effects of the compared proportional counters are the same (hence the term "identical"), subtraction of the shorter counter's results from the longer counter's results effectively creates a virtual proportional counter volume equal to the difference in the two counters' volumes but absent of any end effects.…”

Section: Absolute Gas Counting Methodsmentioning

confidence: 99%

Shielding concepts for low-background proportional counter arrays in surface laboratories

Aalseth

Humble

Mace

et al. 2016

Applied Radiation and Isotopes

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Development of ultra low background gas proportional counters has made the contribution from naturally occurring radioactive isotopes -primarily α and β activity in the uranium and thorium decay chains -inconsequential to instrumental sensitivity levels when measurements are performed in above ground surface laboratories. Simple lead shielding is enough to mitigate against gamma rays as gas proportional counters are already relatively insensitive to naturally occurring gamma radiation. The dominant background in these surface laboratory measurements using ultra low background gas proportional counters is due to cosmic ray generated muons, neutrons, and protons. Studies of measurements with ultra low background gas proportional counters in surface and underground laboratories as well as radiation transport Monte Carlo simulations suggest a preferred conceptual design to achieve the highest possible sensitivity from an array of low background gas proportional counters when operated in a surface laboratory. The basis for a low background gas proportional counter array and the preferred shielding configuration is reported, especially in relation to measurements of radioactive gases having low energy decays such as 37 Ar.

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“…By calculating the difference in net count rates and treating the active volume as the difference in volume between any pair of counters, end effects can be eliminated [2]. This capability will allow for the validation and use of low-level, gaseous radionuclide calibration standards in PNNL's shallow underground laboratory.…”

Section: Initial Characterization Of Unequal-length Low-background Pmentioning

confidence: 99%

Initial characterization of unequal-length, low-background proportional counters for absolute gas-counting applications

Mace

Aalseth

Bonicalzi

et al. 2013

AIP Conference Proceedings

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Characterization of two sets of custom unequal length proportional counters is underway at Pacific Northwest National Laboratory (PNNL). These detectors will be used in measurements to determine the absolute activity concentration of gaseous radionuclides (e.g., 37 Ar). A set of three detectors has been fabricated based on previous PNNL ultra-low-background proportional counter designs and now operate in PNNL's shallow underground counting laboratory. A second set of four counters has also been fabricated using clean assembly of Oxygen-Free High-Conductivity copper components for use in a shielded above-ground counting laboratory. Characterization of both sets of detectors is underway with measurements of background rates, gas gain, and energy resolution. These results will be presented along with a shielding study for the above-ground cave.

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Primary radioactive gas standards (excluding radon)

Cited by 20 publications

References 14 publications

Comparison of tritiated-water standards by liquid scintillation for calibration of a new Standard Reference Material®

Comparison of tritiated-water standards by liquid scintillation for calibration of a new Standard Reference Material®

Shielding concepts for low-background proportional counter arrays in surface laboratories

Initial characterization of unequal-length, low-background proportional counters for absolute gas-counting applications

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