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

Anita Crompton,Kelum Gamage,Andrew Wilson,Steven Bell,Alex Jenkins,Divyesh Trivedi

doi:10.3390/s18061842

Abstract

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.

Highlights

IntroductionDue to the short range of alpha particles in air (approximately 5 cm depending on energy), detectors which require direct interaction to detect alpha radiation are required to be operated in very close proximity to any surface under examination
Due to the short range of alpha particles in air, detectors which require direct interaction to detect alpha radiation are required to be operated in very close proximity to any surface under examination
The increase in the cps produced by a Xe atmosphere, especially as the detection rate may be as much as doubled, does indicate that the use of a flow of this gas could be useful in the development of an alpha detection system

Summary

Introduction

Due to the short range of alpha particles in air (approximately 5 cm depending on energy), detectors which require direct interaction to detect alpha radiation are required to be operated in very close proximity to any surface under examination. They transfer energy to and ionise the air The relaxation from this excited state causes the emission of optical photons. These photons have a much greater mean free path than the original alpha particle and provide a possible opportunity for stand-off alpha detection. This radioluminescence is mainly in the 300–400 nm wavelength range [1,2]. In this range, there is much interference from background light, either from the sun or from indoor

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Conclusion