Could a UVTron Flame Detector be Used for Standoff Alpha Detection in the Field in Normal Lighting Conditions?

Crompton, A.J. and Gamage, K.A.A. (2019) Could a UVTron Flame Detector be Used for Standoff Alpha Detection in the Field in Normal Lighting Conditions? 2019 Nuclear Frontiers Conference, Bristol, UK, 15 Jan 2019.

Abstract

A means to detect alpha emitting materials from a distance has long been sought to overcome the difficulties of traditional alpha detection methods. Traditional detectors require direct interaction with alpha particles, which means that detectors are deployed at around 1 cm from the surface under scrutiny. This makes detection time consuming, and in mixed radiation fields makes the work potentially hazardous to operators. As alpha particles travel they interact with the air, transferring their energy and causing ionisation. This causes the air to emit photons in the ultraviolet (UV) wavelength range (<400 nm). These photons travel in the order of km, much further than the alpha itself, and offer a possible mechanism for a stand-off detector system. Although most of the photons emitted are in the 300 – 400 nm wavelength range (UVA and UVB) there is significant sunlight in this range, giving a very high background that interferes with detection. However, some of the emitted photons are in the UVC wavelength range (180-280 nm), the range in which sunlight is absorbed in the atmosphere. This gives a very low background. A solar-blind UVC detector used in fire alarm systems, the UVTron (Hamamatsu), has been tested for its possible application as an alpha-induced UVC radioluminescence sensor. It has successfully detected a 210Po source of 6.95MBq activity from a distance of 20 mm using UVC radioluminescence. A flow of gas over the source has also been tested with the UVTron, which in the case of xenon increased the signal greatly, doubling it in one instance. The UVTron is susceptible to gamma and beta radiation and its use in any detector design would have to allow for this fact. However, the sensor can be used in normal lighting conditions due to its very low background count, and has the potential to be used in a stand-off, scanning detector system to detect UVC from alpha-induced radioluminescence.

• Item Type: Conference or Workshop Item
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Gamage, Professor Kelum
• Authors: Crompton, A.J., and Gamage, K.A.A.
• College/School: College of Science and Engineering > School of Engineering > Systems Power and Energy