UVC Detection as a Potential for Alpha Particle Induced Air Fluorescence Localisation

As part of the decommissioning process, Plutonium-Contaminated Material (PCM) has to be identified, so it can be disposed of appropriately. Most conventional alpha detectors are only effective at relatively short range. This puts personnel in close proximity to the radiation exposure from this and other types of radiation. Alpha particles cause ionisation in air resulting in the emission of ultraviolet (UV) photons. These have a considerably longer mean free path than alpha particles, providing an avenue to detect alpha contamination from a distance. However, the intensity of this UV light is exceedingly small in comparison to natural daylight, making detection difficult in the field. Although the majority of emitted photons are in the 300 to 400 nm wavelength range, it may be possible to detect those in the UVC range (180 – 280 nm) as natural UVC is blocked by Earth’s atmosphere. UVC detection is already used in the detection of fires and corona discharge. A group of such detectors have undergone a series of tests to determine their suitability for detecting UVC emissions from alpha particle induced air fluorescence. Results to date have shown that long range UVC detection and location is possible with these detectors