scholarly journals The Simulated Characterization and Suitability of Semiconductor Detectors for Strontium 90 Assay in Groundwater

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 984
Author(s):  
Graeme Turkington ◽  
Kelum A. A. Gamage ◽  
James Graham
Keyword(s):  
Surface Area ◽  
Limit Of Detection ◽  
Semiconductor Detectors ◽  
Point Energy ◽  
Carbon 14 ◽  
Beta Emitters ◽  
Nuclear Decommissioning ◽  
Strontium 90 ◽  
Potassium 40 ◽  
Yttrium 90

This paper examines the potential deployment of a 10 mm × 10 mm × 1 mm cadmium telluride detector for strontium-90 measurement in groundwater boreholes at nuclear decommissioning sites. Geant4 simulation was used to model the deployment of the detector in a borehole monitoring contaminated groundwater. It was found that the detector was sensitive to strontium-90, yttrium-90, caesium-137, and potassium-40 decay, some of the significant beta emitters found at Sellafield. However, the device showed no sensitivity to carbon-14 decay, due to the inability of the weak beta emission to penetrate both the groundwater and the detector shielding. The limit of detection for such a sensor when looking at solely strontium-90 decay was calculated as 323 BqL−1 after a 1-h measurement and 66 BqL−1 after a 24-h measurement. A gallium-arsenide (GaAs) sensor with twice the surface area, but 0.3% of the thickness was modelled for comparison. Using this sensor, sensitivity was increased, such that the limit of detection for strontium-90 was 91 BqL−1 after 1 h and 18 BqL−1 after 24 h. However, this sensor sacrifices the potential to identify the present radionuclides by their end-point energy. Additionally, the feasibility of using flexible detectors based on solar cell designs to maximise the surface area of detectors has been modelled.

scholarly journals Minimum Detectable Activity of Pb-210 in Skull From In vivo Measurements: Insights From the Literature

2021 ◽  
Vol 9 ◽  
Author(s):  
Xiangpeng Meng ◽  
Yuanyuan Liu ◽  
Bin Wu ◽  
Jianping Cheng ◽  
Li Wang ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Minimum Detectable Activity ◽  
Active Area ◽  
Semiconductor Detectors ◽  
Background Count ◽  
Radon Exposure ◽  
Detectable Activity ◽  
Retrospective Assessment ◽  
History Of

To address the urgent need for the retrospective assessment of the health conditions of people with a history of appreciable radon exposure, a novel technique that directly measures the characteristic γ-rays emitted from Pb-210 in the living skull was developed. Since the first pioneering study in 1968, this technique has experienced continued advancement over more than half a century, where the limit of detection of Pb-210 is a common criterion to assess the performance of the measuring devices. However, researchers have defined the limit of detection in assorted ways, and the measurement conditions often greatly differ from study to study, both of which significantly challenge interstudy comparisons and obscure how various factors make their impacts. In this work, we reanalyze the reported results in the literature according to the minimum detectable activity (MDA) defined by Currie and investigate the effects of key elements therein. Firstly, we focus on the reported background count rates and analyze their dependence on detector’s energy resolution and active area. Secondly, we turn to the reported calibration factors and conduct analysis in the same manner. Thirdly, we calculate MDA for each study and monitor its dependence on the active area of detector and measurement duration. In the limit of the largest achievable active area (∼75000 mm2), it is found that the asymptotic MDA is approximately 6 (4) Bq and 15 (11) Bq under 30 (60) min measurement using NaI-CsI scintillator and HPGe semiconductor detectors, respectively. Finally, we discuss these asymptotic MDA in the context of estimated Pb-210 activity in the skull resulted from a hypothetical history of radon exposure.

Strahlenbehandlung von Hautkrankheiten mit Strontium 90/Yttrium 90

1960 ◽  
Vol 211-211 (1) ◽  
pp. 389-392 ◽  
Author(s):  
W. Sevin ◽  
R. Anger
Keyword(s):  
Strontium 90 ◽  
Yttrium 90

Direct Absorption of Dissolved Strontium-90 and Yttrium-90 by Tadpoles of Rana temporaria

Nature ◽  
1958 ◽  
Vol 182 (4644) ◽  
pp. 1242-1243 ◽  
Author(s):  
J. W. LUCAS ◽  
D. C. PICKERING
Keyword(s):  
Rana Temporaria ◽  
Direct Absorption ◽  
Strontium 90 ◽  
Yttrium 90

scholarly journals Evaluation of Sample Recovery Efficiency for Bacteriophage P22 on Fomites

2012 ◽  
Vol 78 (22) ◽  
pp. 7915-7922 ◽  
Author(s):  
Amanda B. Herzog ◽  
Alok K. Pandey ◽  
David Reyes-Gastelum ◽  
Charles P. Gerba ◽  
Joan B. Rose ◽  
...  
Keyword(s):  
Surface Area ◽  
Limit Of Detection ◽  
Sampling Time ◽  
Wetting Agent ◽  
Galvanized Steel ◽  
Quantitative Microbial Risk Assessment ◽  
Recovery Efficiency ◽  
Bacteriophage P22 ◽  
Surface Areas ◽  
Sample Recovery

ABSTRACTFomites are known to play a role in the transmission of pathogens. Quantitative analysis of the parameters that affect sample recovery efficiency (SRE) at the limit of detection of viruses on fomites will aid in improving quantitative microbial risk assessment (QMRA) and infection control. The variability in SRE as a function of fomite type, fomite surface area, sampling time, application media, relative humidity (rH), and wetting agent was evaluated. To quantify the SRE, bacteriophage P22 was applied onto fomites at average surface densities of 0.4 ± 0.2 and 4 ± 2 PFU/cm2. Surface areas of 100 and 1,000 cm2of nonporous fomites found in indoor environments (acrylic, galvanized steel, and laminate) were evaluated with premoistened antistatic wipes. The parameters with the most effects on the SRE were sampling time, fomite surface area, wetting agent, and rH. At time zero (the initial application of bacteriophage P22), the SRE for the 1,000-cm2fomite surface area was, on average, 40% lower than that for the 100-cm2fomite surface area. For both fomite surface areas, the application medium Trypticase soy broth (TSB) and/or the laminate fomite predominantly resulted in a higher SRE. After the applied samples dried on the fomites (20 min), the average SRE was less than 3%. A TSB wetting agent applied on the fomite improved the SRE for all samples at 20 min. In addition, an rH greater than 28% generally resulted in a higher SRE than an rH less than 28%. The parameters impacting SRE at the limit of detection have the potential to enhance sampling strategies and data collection for QMRA models.

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