Proton Excitation of the 1300-Å Continuum in Argon

Hurst, G. S.; Bortner, T.E.; Strickler, T. D.

doi:10.1063/1.1670433

Cited by 6 publications

(3 citation statements)

References 5 publications

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“…Five different gases were flowed over the source and the fluorescence measured was compared to an air atmosphere. These were selected following research into gases which were both likely to ionise at suitable energies and to emit photons of the required wavelength [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. Although several of the studies used focus on ionisation of gases [ 21 , 22 , 23 ], this leads to secondary electrons which are believed to generate the fluorescence photons [ 16 ].…”

Section: Resultsmentioning

confidence: 99%

“…Hurst et al [ 16 ] in their experiments using protons to excite gases, found that it was preferable for the gas to flow through the gas cell they used rather than having a static gas atmosphere, as the former increased the amount of light intensity. The effects of various gases on alpha-induced fluorescence have been investigated [ 7 , 16 , 17 , 18 , 19 , 20 ]. However, to address the suitability for field operations and in light of Hurst et al’s findings, a flow of gas over the source was tested.…”

Section: Methodsmentioning

confidence: 99%

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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: Methodsmentioning

confidence: 99%

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

View full text Add to dashboard Cite

show abstract

“…As a flow over the source does not depend on a purged gas atmosphere, it may be more suited to a wider application in the field, where the contamination could be in a large space or spaces containing personnel. A flow of gas within a purged atmosphere when researching the use of protons to excite gases has been found to be preferable to a static atmosphere as it increases the intensity of the radioluminescence [ 23 ]; hence, the use of a flow is not unprecedented for research in this area.…”

Section: Methodsmentioning

confidence: 99%

Gas Flow to Enhance the Detection of Alpha-Induced Air Radioluminescence Based on a UVTron Flame Sensor

Crompton

Gamage

Bell

et al. 2018

Sensors

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In many field applications where alpha-induced radioluminescence (or so-called UV fluorescence) could potentially be used for stand-off detection of alpha-emitting materials, it may not be possible to create a fully purged gas atmosphere. Hence, an alternative gas delivery method to utilise the radioluminescence enhancing properties of gases has been investigated, with the novel results from this presented herewithin. A solar blind ultraviolet C (UVC) sensor (UVTron R9533, Hamamatsu, Japan) has been used to detect changes in the signal in the UVC wavelength range (180–280 nm), where gases of Ar, Xe, Ne, N2, Kr, and P-10 were flowed over a 6.95 MBq 210Po source using a narrow diameter pipe close to the source. In comparison with an air atmosphere, there was an increase in signal in all instances, the greatest being the flow of Xe, which in one instance greater than doubled the average counts per second. This increase in signal could prove beneficial in the design of a stand-off alpha detector to detect the very small UVC radioluminescence signals from alpha-emitting materials found in nuclear decommissioning environments.

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Ionization of the Noble Gases by Protons: Jesse Effects as a Function of Pressure

Parks

Hurst

Stewart

et al. 1972

The Journal of Chemical Physics

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A new method has been developed to measure W, the ratio of the energy lost by a proton to the number of ion pairs produced when these particles interact with a gas. In this method, protons are Rutherford scattered from a beam by a thin gold foil into a W cell where total gas ionization is measured. The number of protons scattered into the W cell is measured with a silicon surface barrier detector, and the energy lost to the gas is calculated from stopping power data. Most of the protons pass through the thin gold foil and enter an emission cell where emission spectra are studied with a vacuum ultraviolet scanning monochromator. At 400 torr for pure gases the following values of W (eV per ion pair) were found for 3.6-MeV protons: He, 4S.2±0.9; Ne, 39.3±0.8; Ar, 26.6±0.S; Kr, 23.0±0.S; Xe, 20.S±1.2; N2, 36.6±0.7. No appreciable pressure dependence was observed for the pure gases. The Jesse effect, which is the increase in ionization observed when impurities are added to certain gases, was studied as a function of concentration and pressure for mixtures of C2H., C2H2, and CO2 with Ar. At small concentrations of CJI. or C2H2 the Jesse effect decreases as the total gas pressure increases. These data, along with other facts cited in this paper, tend to confirm an energy pathways model for argon. Based on a comparison of our data with this model, we deduce the values 6.SXlO-1o and 1.1X1Q-9 cm S seC I for the rate constants for producing the Jesse effect from the IPI (1048 A) resonance state of argon by collisions with CJI. and Ct H2, respectively. W values were also studied as a function of pressure and concentration for mixtures of Ne, Ar, Kr, and Xe with He. The dependence of W on pressure and concentration was similar to that of argon. PARKS, HURST, STEWART, AND WEIDNER MONOCHROMATOR

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Proton Excitation of the 1300-Å Continuum in Argon

Cited by 6 publications

References 5 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

Gas Flow to Enhance the Detection of Alpha-Induced Air Radioluminescence Based on a UVTron Flame Sensor

Ionization of the Noble Gases by Protons: Jesse Effects as a Function of Pressure

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