The simulated characterization and suitability of semiconductor detectors for strontium 90 assay in groundwater

Turkington, G., Gamage, K. A.A. and Graham, J. (2021) The simulated characterization and suitability of semiconductor detectors for strontium 90 assay in groundwater. Sensors, 21(3), 984. (doi: 10.3390/s21030984)

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Abstract

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.

Item Type:Articles
Additional Information:This research was funded by the Nuclear Decommissioning Authority and School of Engineering, University of Glasgow.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Gamage, Professor Kelum and Turkington, Mr Graeme
Authors: Turkington, G., Gamage, K. A.A., and Graham, J.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
College of Science and Engineering > School of Engineering > Systems Power and Energy
Journal Name:Sensors
Publisher:MDPI
ISSN:1424-8220
ISSN (Online):1424-8220
Published Online:02 February 2021
Copyright Holders:Copyright © 2021 The Authors
First Published:First published in Sensors 21(3): 984
Publisher Policy:Reproduced under a Creative Commons License

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