ViridiScreen is a very sensitive and, importantly, robust alpha detection system, which uses the measurement of photons derived from the interaction of alpha particles with nitrogen in the air to determine the gross alpha activity on a surface. We are delighted that Sellafield Ltd has chosen to trial the use of ViridiScreen for a particularly challenging application on site. Kym and John have trained a member of Sellafield staff to use ViridiScreen in preparation for the work.