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Blain E, Nishikawa K, Faye SA, Roselan A, Burn AG, Torres MA, Semkow TM. Detection Capability of 89Sr and 90Sr Using Liquid Scintillation Counting. HEALTH PHYSICS 2023; 125:123-136. [PMID: 37384913 PMCID: PMC10361665 DOI: 10.1097/hp.0000000000001698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/01/2023]
Abstract
ABSTRACT We developed a new method for simultaneous determination of 89Sr and 90Sr with an emphasis on detectability. The samples were digested, and Sr was chemically purified followed by a single count on a liquid scintillation counter in three windows overlapping the 90Sr, 89Sr, and 90Y peaks. Gamma spectrometry was used to measure 85Sr, added for chemical recovery. The method was tested on 18 water samples spiked at levels from 9 to 242 Bq of 89Sr and 90Sr, with either single radionuclides or their mixtures. In addition, eight method blanks were measured. The data were analyzed numerically by solving a system of linear equations for 89Sr and 90Sr activities as analytes and 90Y activity as a participating component. The total uncertainties of the results were calculated numerically using variances and covariances. The average bias from the known activities was -0.3% (range from -3.6 to 3.1%) for 90Sr and - 1.5% (range from -10.1 to 5.1%) for 89Sr. The En-scores were within -1.0 and 1.0 at 95% confidence level. The detection capabilities of this method were determined by means of the decision threshold LC and the limit of detection referred to as the minimum detectable activity. All relevant uncertainties were propagated into the LC and minimum detectable activity. In addition, detection limits were calculated for the purpose of Safe Drinking Water Act monitoring. The detection capabilities were compared with the regulatory requirements in the US and EU for food and water. For samples spiked with either pure 89Sr or 90Sr, false positives were observed for the opposite radionuclide exceeding the above LC values. This was attributed to interference by the spiked activity. A new method was developed to calculate decision and detectability curves in the presence of interference.
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Affiliation(s)
- Ezekiel Blain
- Wadsworth Center, New York State Department of Health, Albany, NY 12201, USA
| | - Kimi Nishikawa
- Wadsworth Center, New York State Department of Health, Albany, NY 12201, USA
| | - Sherry A. Faye
- Wadsworth Center, New York State Department of Health, Albany, NY 12201, USA
- Department of Environmental Health Sciences, School of Public Health, University at Albany (SUNY), Rensselaer, NY 12144, USA
| | - Amy Roselan
- Wadsworth Center, New York State Department of Health, Albany, NY 12201, USA
| | - Adam G. Burn
- Wadsworth Center, New York State Department of Health, Albany, NY 12201, USA
- Department of Environmental Health Sciences, School of Public Health, University at Albany (SUNY), Rensselaer, NY 12144, USA
| | - Miguel A. Torres
- Wadsworth Center, New York State Department of Health, Albany, NY 12201, USA
| | - Thomas M. Semkow
- Wadsworth Center, New York State Department of Health, Albany, NY 12201, USA
- Department of Environmental Health Sciences, School of Public Health, University at Albany (SUNY), Rensselaer, NY 12144, USA
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Rondahl SH, Ramebäck H. Evaluation of different methods for measuring 89Sr and 90Sr: Measurement uncertainty for the different methods as a function of the activity ratio. Appl Radiat Isot 2018; 140:87-95. [PMID: 29966938 DOI: 10.1016/j.apradiso.2018.06.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 06/15/2018] [Accepted: 06/20/2018] [Indexed: 10/28/2022]
Abstract
In case of a radiological emergency situation involving e.g. fission of uranium or plutonium, analysis of radioactive strontium will be of importance. The primary radionuclides of interest are 90Sr, its progeny 90Y and 89Sr. A few days following an event, 89Sr will be the predominant radioisotope of strontium. Most methods found in the literature are valid and applicable when measuring 90Sr, but when samples contain both 89Sr/90Sr interference problematics arise. How these interferences are dealt with will have an effect on the uncertainty of the 90Sr determination. This work aims at evaluating three measurement approaches, all mentioned in the literature, with respect to the measurement uncertainty when determining 90Sr in an emergency preparedness situation and to propose a suitable measurement strategy.
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Affiliation(s)
- Stina Holmgren Rondahl
- Swedish Defence Research Agency (FOI), CBRN Defence and Security, Cementvägen 20, 901 82 Umeå, Sweden.
| | - Henrik Ramebäck
- Swedish Defence Research Agency (FOI), CBRN Defence and Security, Cementvägen 20, 901 82 Umeå, Sweden; Chalmers University of Technology, Department of Chemistry and Chemical Engineering, Nuclear Chemistry, 412 96 Göteborg, Sweden
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Shirono K, Unno Y, Furukawa R, Yonezawa C. A practical evaluation of measurement uncertainty in gamma-ray efficiency curve determination through an analytical approach. Appl Radiat Isot 2017; 121:131-141. [PMID: 28092868 DOI: 10.1016/j.apradiso.2016.12.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 10/21/2016] [Accepted: 12/05/2016] [Indexed: 10/20/2022]
Abstract
An example of uncertainty evaluation of an efficiency curve is reported. In the applied method, the efficiency curve is determined through the weighted least square method based on measured efficiencies employing a mixed-radionuclide standard source. The variance-covariance matrix of the efficiencies is determined by evaluating the uncertainties of the counting, the calibrated radioactivities, the correction factors for true coincidence summing, and the inadequacy of the fitting function. The proposed method can be a basis to develop a more general procedure.
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Affiliation(s)
- Katsuhiro Shirono
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8565, Japan.
| | - Yasuhiro Unno
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8565, Japan.
| | - Rio Furukawa
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8565, Japan.
| | - Chushiro Yonezawa
- Japan Institute of International Affairs (JIIA), Toranomon Mitsui Bldg., 3-8-1 Kasumigaseki, Chiyoda-ku, Tokyo 100-0013, Japan.
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Combined method for the fast determination of pure beta emitting radioisotopes in food samples. J Radioanal Nucl Chem 2016. [DOI: 10.1007/s10967-016-4960-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Kanisch G. Generalized evaluation of environmental radioactivity measurements with UncertRadio. Part I: Methods without linear unfolding. Appl Radiat Isot 2016; 110:28-41. [DOI: 10.1016/j.apradiso.2015.12.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 11/30/2015] [Accepted: 12/03/2015] [Indexed: 10/22/2022]
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