Detection of Alpha-induced radioluminescence in the ultraviolet C range for Nuclear Decommissioning Applications

The close range of traditional alpha radiation detectors makes detection time-consuming and potentially hazardous. Alpha-induced radioluminescence in the ultraviolet C (UVC) wavelength range (180-280 nm) may be the mechanism through which stand-off detection can be achieved. The UVTRON (Hamamatsu) solar-blind flame sensor is sensitive to photons of wavelengths between185 – 260 nm and has a low background count due to the absorption of natural UVC in the atmosphere. It has successfully detected a Po-210 source of 6.95 MBq from 20 mm distance, and flowing gases over the source, especially xenon, has shown the signal can be significantly increased. As a mature technology, which is small, robust, low-cost and easily available, the UVTRON would be ideal for inclusion in a scanning, stand-off, alpha detection system. It has been shown, however, to be sensitive to gamma and beta radiation and this would need to be taken into account in any system design. However, that this sensor can be used in normal lighting conditions makes it a potential candidate for stand-off alpha detection in field conditions, and results of distance, scanning and detection experiments support this.