Fluorescence-Assisted Gamma Spectrometry for Surface Contamination Analysis

Ihantola, Sakari; Sand, Johan; Perajärvi, K.; Toivonen, Juha; Toivonen, H.

doi:10.1109/tns.2013.2238249

Cited by 12 publications

(20 citation statements)

References 14 publications

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“…Nitrogen showed only a small increase, which could be accounted for within the uncertainty and therefore may not be an actual observed increase. As this is the primary constituent of air and it is known to enhance fluorescence in the 300–400 nm wavelength range [ 1 , 2 , 5 , 6 , 8 , 9 ] this result was unexpected. Sand et al [ 7 ] found an increase in fluorescence in the deep UV (around 260 nm) using a nitrogen purge.…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, detectors which require direct contact with alpha particles need to be in close proximity to any surface or object to determine if alpha contamination is present, at a distance of less than the mean free path of the alpha particles. This causes a number of issues, as documented by other researchers [ 1 , 2 , 3 ]. As objects to be monitored may be in a mixed radiation environment, personnel carrying out detection activities may require personal protective equipment (PPE) and have limited time in which they can safely operate.…”

Section: Introductionmentioning

confidence: 93%

See 1 more Smart Citation

First Results of Using a UVTron Flame Sensor to Detect Alpha-Induced Air Fluorescence in the UVC Wavelength Range

Crompton

Gamage

Bell

et al. 2017

Sensors

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In this work, a robust stand-off alpha detection method using the secondary effects of alpha radiation has been sought. Alpha particles ionise the surrounding atmosphere as they travel. Fluorescence photons produced as a consequence of this can be used to detect the source of the alpha emissions. This paper details experiments carried out to detect this fluorescence, with the focus on photons in the ultraviolet C (UVC) wavelength range (180–280 nm). A detector, UVTron R9533 (Hamamatsu, 325-6, Sunayama-cho, Naka-ku, Hamamatsu City, Shizuoka Pref., 430-8587, Japan), designed to detect the UVC emissions from flames for fire alarm purposes, was tested in various gas atmospheres with a 210Po alpha source to determine if this could provide an avenue for stand-off alpha detection. The results of the experiments show that this detector is capable of detecting alpha-induced air fluorescence in normal indoor lighting conditions, as the interference from daylight and artificial lighting is less influential on this detection system which operates below the UVA and UVB wavelength ranges (280–315 nm and 315–380 nm respectively). Assuming a standard true1r2 drop off in signal, the limit of detection in this configuration can be calculated to be approximately 240 mm, well beyond the range of alpha-particles in air, which indicates that this approach could have potential for stand-off alpha detection. The gas atmospheres tested produced an increase in the detector count, with xenon having the greatest effect with a measured 52% increase in the detector response in comparison to the detector response in an air atmosphere. This type of alpha detection system could be operated at a distance, where it would potentially provide a more cost effective, safer, and faster solution in comparison with traditional alpha detection methods to detect and characterise alpha contamination in nuclear decommissioning and security applications.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 93%

First Results of Using a UVTron Flame Sensor to Detect Alpha-Induced Air Fluorescence in the UVC Wavelength Range

Crompton

Gamage

Bell

et al. 2017

Sensors

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show abstract

“…Since the optical method is not limited by the range of the particle, significant advancements can be achieved in decontamination and safety inspection applications. Furthermore, it is possible to monitor contamination through ultraviolet (UV) transmitting materials such as plexi and lead glass, without breaching the containment [5,6]. The technique has been demonstrated in field tests by independent research units and it has the potential to evolve into an industry-standard procedure in the future [3][4][5]7].…”

Section: Introductionmentioning

confidence: 99%

Radioluminescence yield of alpha particles in air

Sand¹,

Ihantola²,

Perajärvi³

et al. 2014

New J. Phys.

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Alpha particles can be detected by measuring the radioluminescence light which they induce when absorbed in air. The light is emitted in the near ultraviolet region by nitrogen molecules excited by secondary electrons. The accurate knowledge of the radioluminescence yield is of utmost importance for novel radiation detection applications utilizing this secondary effect. Here, the radioluminescence yield of an alpha particle is investigated as a function of energy loss in air for the first time. Also, the total radioluminescence yield of the particle is measured with a carefully calibrated 239 Pu emitter used in the experiments. The obtained results consistently indicate that alpha particles generate ± 19 3 photons per one MeV of energy released in air at normal pressure (temperature°2 2 C, relative humidity 43%) and the dependence is found to be linear in the studied energy range from 0.3 MeV to 5.1 MeV. The determined radioluminescence yield is higher than previously reported for alpha particles and similar to the radioluminescence yield of electrons at comparable energies. This strengthens the evidence that the luminescence induced by charged particles is mostly proportional to the energy loss in the media and not very sensitive to the type of primary particle.Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. New J. Phys. 16 (2014) 053022 J Sand et al New J. Phys. 16 (2014) 053022 J Sand et al 3 New J. Phys. 16 (2014) 053022 J Sand et al 4 New J. Phys. 16 (2014) 053022 J Sand et al 5 New J. Phys. 16 (2014) 053022 J Sand et al 6 New J. Phys. 16 (2014) 053022 J Sand et al 7 New J. Phys. 16 (2014) 053022 J Sand et al 8 New J. Phys. 16 (2014) 053022 J Sand et al 9 New J. Phys. 16 (2014) 053022 J Sand et al 10

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“…Determination of alpha particle emitting radionuclides causing the UV light can be continued with a position-sensitive UV-gated gamma-spectrometry technique, jointly developed by STUK and the Technical University of Tampere, Finland [5,6]. This measurement is realized by gating the HPGe detector with UV photons.…”

Section: αUv-gamma Coincidence Spectrometrymentioning

confidence: 99%

“…This measurement is realized by gating the HPGe detector with UV photons. The technique was tested in [6] by measuring simultaneously 241 Am and 133 Ba sources. In the singles spectrum 241 Am 59.5 keV gamma-ray peak is barely visible, while in the UV-gated spectrum it is very well pronounced.…”

Section: αUv-gamma Coincidence Spectrometrymentioning

confidence: 99%

Novel Coincidence Techniques, Detectors and Concepts for Safety, Security and Safeguards

Perajärvi¹

2014

Acta Phys. Pol. B

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Research and development (R&D) projects are used to maintain and improve STUK's ability to act and advice other competent authorities correctly in conditions involving nuclear and other radioactive materials. Examples from recent or ongoing in-field and laboratory R&D projects are given. All projects introduced are related to passive detection of alpha particle emitting nuclides or neutron sources.

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Fluorescence-Assisted Gamma Spectrometry for Surface Contamination Analysis

Cited by 12 publications

References 14 publications

First Results of Using a UVTron Flame Sensor to Detect Alpha-Induced Air Fluorescence in the UVC Wavelength Range

First Results of Using a UVTron Flame Sensor to Detect Alpha-Induced Air Fluorescence in the UVC Wavelength Range

Radioluminescence yield of alpha particles in air

Novel Coincidence Techniques, Detectors and Concepts for Safety, Security and Safeguards

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