Calibration of Ge gamma-ray spectrometers for complex sample geometries and matrices

Semkow, Thomas M.; Bradt, Clayton J.; Beach, S.E.; Haines, Douglas K.; Khan, Abdul Jabbar; Bari, Abdul; Torres, Miguel; Marrantino, Joseph C.; Syed, Umme-Farzana; Kitto, Michael E.; Hoffman, Timothy J.; Curtis, P.

doi:10.1016/j.nima.2015.07.064

Cited by 9 publications

(5 citation statements)

References 13 publications

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“…The NIST traceable mixed-gamma radionuclide standards containing 241 Am, 109 Cd, 57 Co, 139 Ce, 203 Hg, 113 Sn, 85 Sr, 137 Cs, 54 Mn, 88 Y, 65 Zn, 60 Co were provided by EZ Analytics, Atlanta, GA, USA. The radionuclides and their standardized gamma energies are listed elsewhere (Semkow et al, 2015). Gamma-ray spectra were acquired using Apex Gamma software of Mirion Technologies (Canberra) Inc. (Meriden, CT, USA) however, the spectra were analyzed using Genie 2000 software for the sediment sample as well as for efficiency calibration.…”

Section: Gamma Spectrometrymentioning

confidence: 99%

“…Gamma spectrometry is extensively used for 238 U, 232 Th, 226 Ra, and 40 K determination in environmental samples because of its simplicity in terms of sample preparation. It can simultaneously perform multi-nuclide determinations based on the detection of photon emissions and, therefore, does not require sophisticated sample treatment, however, it requires precise calibration of gamma detectors with NIST traceable standards or Monte Carlo methods (Semkow et al, 2015;Azbouche et al, 2015). Gamma spectrometry can be easily applied to determine 238 U, 226 Ra, and 235 U in environmental as well as in food samples simultaneously without any radiochemical separation.…”

Section: Introductionmentioning

confidence: 99%

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Uranium Series Disequilibrium and Precision Measurement of Radionuclides Activity in Sediment Sample Using Low Background Gamma Spectrometry

Khan,

Syed,

Roselan

et al. 2023

GEP

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Low background gamma spectrometry was used to measure the radionuclides activity of 238 U, 232 Th, and 235 U series as well as 40 K and 137 Cs in a sediment sample. The goal of the study was to measure the 238 U (63.3 keV peak of 234 Th; 1001 keV peak of 234m Pa) and 235 U (143.76 keV, 163.33 keV, and 205.31 keV peaks) activity by low background gamma spectrometry in sediment sample. 235 U activity in environmental samples is difficult to accurately measure by gamma spectrometry due to its low abundance in nature and low gamma line intensities at 143.76 keV, 163.33 keV, and 205.31 keV. We have shown that by using low background gamma spectrometry, it is possible to accurately measure the 235 U activity in sediment samples. The 235 U activity was measured without using the major peak of 185.7 keV (I γ = 57.2%) which requires interference correction from 186.21 keV of 226 Ra. 226 Ra activity was determined by measuring 222 Rn daughters ( 214 Pb and 214 Bi). The precision and accuracy of the gamma activity measurement in the sediment sample were verified by using the HPGe detectors with Certified Reference Material (CRM) Irish Sea Sediment (IAEA-385). The results obtained for the 63.33 keV energy line of 234 Th are compared with the 1001 keV energy line of 234m Pa. The values of 238 U and 235 U activities, as well as 40 K, 137 Cs, and 226 Ra, agreed with the certificate values of CRM. The results show that the 238 U is in equilibrium with its daughters ( 234 Th, 234m Pa, and 210 Pb). 232 Th is also in equilibrium with its daughters ( 228 Ra, 212 Pb, 212 Bi and 208 Tl). 235 U/ 238 U activity ratio of 0.046 ± 0.

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Section: Gamma Spectrometrymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Uranium Series Disequilibrium and Precision Measurement of Radionuclides Activity in Sediment Sample Using Low Background Gamma Spectrometry

Khan,

Syed,

Roselan

et al. 2023

GEP

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“…It was shown, using Monte-Carlo (MC) simulation, that the Ge detector peak efficiency dropped with increased granularity [6]. However, this effect has not been seen experimentally for grains of soil or polystyrene much smaller than the container size, in which spiking solution occupied an interstitial space [7].…”

Section: Introductionmentioning

confidence: 99%

Monte Carlo Simulation Study of Hot-Particle Detection in Voluminous Samples by Gamma Spectrometry

Chu¹,

Burn²,

Bradt³

et al. 2021

JAMP

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In this work, we addressed the inhomogeneity problem in gamma spectrometry caused by hot particles, which are dispersed into environment from large nuclear reactor accidents such as at Chernobyl and Fukushima. Using Monte Carlo simulation, we have determined the response of a gamma spectrometer to individual and grouped hot particles randomly distributed in a soil matrix of 1-L and 0.6-L sample containers. By exploring the fact that the peak-to-total ratio of efficiencies in gamma spectrometry is an empirical parameter, we derived and verified a power-law relationship between the peak efficiency and peak-to-total ratio. This enabled creation of a novel calibration model which was demonstrated to reduce the bias range and bias standard deviation, caused by measuring hot particles, by several times, as compared with the homogeneous calibration. The new model is independent of the number, location, and distribution of hot particles in the samples. In this work, we demonstrated successful performance of the model for a single-peak 137 Cs radionuclide. An extension to multi-peak radionuclide was also derived.

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“…The measured chemical recoveries for 133 Ba tracer varied between 0.75 and 0.96. The absolute efficiencies for the 50-mL and 800-mL geometries were calibrated using a mild acidic solution spiked with a mixed-gamma standard traceable to the National Institute of Standards and Technology (NIST, Gaithersburg, MD, USA) as described elsewhere [21]. Since the calibration standards and samples were water solutions, no density corrections were applied.…”

mentioning

confidence: 99%

Destructive and Nondestructive Determination of <sup>226</sup>Ra and <sup>228</sup>Ra in Drinking Water by Gamma Spectrometry

Khan¹,

Bari²,

Torres³

et al. 2020

JEP

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The Safe Drinking Water Act (SDWA) mandates that the drinking water should be monitored for 226 Ra and 228 Ra isotopes and establishes the Maximum Contaminant Level of 185 mBq/L (5 pCi•L −1) for the sum. In addition, SDWA regulates the Detection Limit (DL) of 37.0 mBq/L (1 pCi/L) for each isotope. The purpose of this work is to develop a working method for the determination of radium isotopes in drinking water satisfying the regulatory requirements of U.S. Environmental Protection Agency by utilizing our extensive experience in low-background gamma spectrometry at this laboratory. Two versions of the method were studied: destructive and non-destructive. Destructive method used the BaSO 4 coprecipitation as well as 133 Ba tracer for chemical recovery. We have used three gamma spectrometers: low-background 102% and 134% efficient with top muon guards, as well as an ultralow-background 140% efficient with full muon guard. We obtained a range of DLs from 5.3 to 22.6 mBq/L for 226 Ra and from 7.4 to 30.4 mBq/L for 228 Ra using the destructive method. For non-destructive method, the DL range was 26.0 to 26.9 mBq/L for 226 Ra and 27.6 to 28.6 mBq/L for 228 Ra using the 140% detector. To verify the methods, 7 to 10 laboratory control samples were spiked with both 226 Ra and 228 Ra at two different activities of 37.0 and 185 mBq/L. The results were evaluated by performing a combined location/variance chi-square test at a right-tail significance of 0.01 (99% Confidence Level), as stipulated by EPA. The verification results passed the chi-square tests at both activity levels. The destructive method can be accomplished using low-background gamma spectrometry, whereas non-destructive method requires ultralow-background gamma spectrometry.

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Calibration of Ge gamma-ray spectrometers for complex sample geometries and matrices

Cited by 9 publications

References 13 publications

Uranium Series Disequilibrium and Precision Measurement of Radionuclides Activity in Sediment Sample Using Low Background Gamma Spectrometry

Uranium Series Disequilibrium and Precision Measurement of Radionuclides Activity in Sediment Sample Using Low Background Gamma Spectrometry

Monte Carlo Simulation Study of Hot-Particle Detection in Voluminous Samples by Gamma Spectrometry

Destructive and Nondestructive Determination of <sup>226</sup>Ra and <sup>228</sup>Ra in Drinking Water by Gamma Spectrometry

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Calibration of Ge gamma-ray spectrometers for complex sample geometries and matrices

Cited by 9 publications

References 13 publications

Uranium Series Disequilibrium and Precision Measurement of Radionuclides Activity in Sediment Sample Using Low Background Gamma Spectrometry

Uranium Series Disequilibrium and Precision Measurement of Radionuclides Activity in Sediment Sample Using Low Background Gamma Spectrometry

Monte Carlo Simulation Study of Hot-Particle Detection in Voluminous Samples by Gamma Spectrometry

Destructive and Nondestructive Determination of &lt;sup&gt;226&lt;/sup&gt;Ra and &lt;sup&gt;228&lt;/sup&gt;Ra in Drinking Water by Gamma Spectrometry

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Destructive and Nondestructive Determination of <sup>226</sup>Ra and <sup>228</sup>Ra in Drinking Water by Gamma Spectrometry