Search for lost or orphan radioactive sources based on NaI gamma spectrometry

Aage, Helle Karina; Korsbech, Uffe C C

doi:10.1016/s0969-8043(02)00222-1

Cited by 54 publications

(27 citation statements)

References 7 publications

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“…Individual bins within each array are mapped on a colour range consisting of contrasting colours. After each data acquisition the measured data is added as a coloured line to the display, making it flow with time (for a brief description see Aage and Korsbech (2003) or the MATLAB user manual).…”

Section: Theory and Methodsmentioning

confidence: 99%

“…(1)(2)(3)(4)(5)) were reset to their background values after each source passage. The background value is simply a value stored immediately before the first source passage.…”

Section: Deviation Display Methodsmentioning

confidence: 99%

“…Often, the Graphical User Interface (GUI) of such a program displays a wide range of user-defined parameters and graphs in real time. From simple parameters like intensity levels of specific radionuclides (Mellander 1998) or Potassium-Stripped Counts (PSC) in a Region of Interest (Hjerpe and Samuelsson 2003) via simple displays like the "waterfall" display (see "rainbow method" in Aage and Korsbech 2003), to more complex filtered displays (Cresswell and Sanderson 2009) and imaging routines (Ziock et al 2003; ). Many methods implemented in such programs have pre-defined alarm levels on different parameters, helping the search crew with indication.…”

mentioning

confidence: 99%

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A deviation display method for visualising data in mobile gamma-ray spectrometry

Kock

Finck

Nilsson

et al. 2010

Applied Radiation and Isotopes

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A real time visualisation method, to be used in mobile gamma-spectrometric search operations using standard detector systems is presented. The new method, called Deviation Display, uses a modified waterfall display to present relative changes in spectral data over energy and time. Using unshielded 137 Cs and 241 Am point sources and different natural background environments, the behaviour of the Deviation Displays is demonstrated and analysed for two standard detector types (NaI(Tl) and HPGe). The Deviation Display enhances positive significant changes while suppressing the natural background fluctuations. After an initialisation time of about 10 minutes this technique leads to a homogeneous display dominated by the background colour, where even small changes in spectral data are easy to discover. As this paper shows, the Deviation Display method works well for all tested gamma energies and natural background radiation levels and with both tested detector systems.

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Section: Theory and Methodsmentioning

confidence: 99%

“…(1)(2)(3)(4)(5)) were reset to their background values after each source passage. The background value is simply a value stored immediately before the first source passage.…”

Section: Deviation Display Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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A deviation display method for visualising data in mobile gamma-ray spectrometry

Kock

Finck

Nilsson

et al. 2010

Applied Radiation and Isotopes

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“…1997, remediation (Giles et.al. 2005), locating point sources (Aage & Korsbech 2003, Hjerpe & Samuelsson 2006, Long & Martin 2007, Kock et.al. 2014, geological mapping for mineral exploration (IAEA 1991, Minty 2011 or epidemiology (Sanderson et.al.…”

Section: Introductionmentioning

confidence: 99%

Operator related attenuation effects in radiometric surveys

Buchanan

Cresswell

Seitz

et al. 2016

Radiation Measurements

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Radiometric surveys using airborne, vehicular mounted or backpack detector systems are increasingly used to identify and evaluate complex distributions of radioactivity in the environment. The signals detected depend on the energy and spatial distribution of radioactive sources, the material properties of the environment and the specific properties of the detector systems employed. Materials in close vicinity to the detector such as housings, and intermediate materials may have a critical impact on detection efficiency, and must therefore be taken into account in calibration. This study evaluates the effect of shielding by the body of the operator in backpack surveys. Controlled experiments using point sources and absorbers, chosen to represent the form and composition of human tissue, were conducted, and coupled to an analytical radiation transport model to estimate attenuation factors for mapping of 137 Cs. In this way generic factors to correct for this effect using portable spectrometers have been determined. The results compare well with observations at sampled calibration sites in Fukushima and the Solway area in Scotland. Reductions of the 137 Cs fullenergy peak intensity between 20% and 30% may be expected depending on operator stature and the offset position of backpack systems. Similar effects may be present for other radiometric systems carried by a human operator.2 Keywords: Environmental radioactivity, gamma ray survey, attenuation by human operator Highlights:• Evaluation of operator effects on radiometric measurements with backpack systems• Potential for similar effects with other radiometric systems• Count rates for radiocaesium full energy peaks are reduced by 20-30%• Count rates for >450 keV, scaling to dose rate, are reduced by approximately 15%

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“…Although field-portable detectors have been frequently used in routine monitoring and hazard assessment studies (Aage and Korsbech, 2003;Hjerpe and Samuelsson, 2003) there have been few thorough attempts to evaluate their potential as an alternative to collecting samples in the field and analysing them in the laboratory. Golosov et al (2000) used a field-portable scintillation detector to study 137 Cs distribution and noted the usefulness of the approach for estimating erosion and sedimentation rates.…”

Section: Introductionmentioning

confidence: 99%