Optimising in situ gamma measurements to identify the presence of radioactive particles in land areas

Rostron, Peter D, Heathcote, John A and Ramsey, Michael H (2014) Optimising in situ gamma measurements to identify the presence of radioactive particles in land areas. Journal of Environmental Radioactivity, 138. pp. 162-169. ISSN 0265931X

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Abstract

High-coverage in situ surveys with gamma detectors are the best means of identifying small hotspots of activity, such as radioactive particles, in land areas. Scanning surveys can produce rapid results, but the probabilities of obtaining false positive or false negative errors are often unknown, and they may not satisfy other criteria such as estimation of mass activity concentrations. An alternative is to use portable gamma-detectors that are set up at a series of locations in a systematic sampling pattern, where any positive measurements are subsequently followed up in order to determine the exact location, extent and nature of the target source. The preliminary survey is typically designed using settings of detector height, measurement spacing and counting time that are based on convenience, rather than using settings that have been calculated to meet requirements. This paper introduces the basis of a repeatable method of setting these parameters at the outset of a survey, for pre-defined probabilities of false positive and false negative errors in locating spatially small radioactive particles in land areas. It is shown that an un-collimated detector is more effective than a collimated detector that might typically be used in the field.

Item Type: Article
Schools and Departments: School of Life Sciences > Biology and Environmental Science
Subjects: H Social Sciences > HD Industries. Land use. Labour > HD1401 Agriculture > HD1635 Utilisation and culture of special classes of lands Including pasture lands, water resources development
Q Science > QC Physics > QC0770 Nuclear and particle physics. Atomic energy. Radioactivity > QC0794.95 Radioactivity and radioactive substances
Depositing User: Catrina Hey
Date Deposited: 28 Oct 2014 11:39
Last Modified: 09 Mar 2017 08:32
URI: http://sro.sussex.ac.uk/id/eprint/50738

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