Imaging of alpha emitters in a field environment

Cameras sensitive to ultraviolet light can be applied to detection of surface contamination induced by alpha particle emitters. When absorbed in air, alpha particles excite nitrogen molecules and the radiative relaxation creates a faint light emission. This radioluminescence can be used for detection purposes, provided that background lighting levels are low. In this work, three low light sensitive camera technologies (CCD, EMCCD and ICCD) were utilized in a nuclear facility, and their performance in detecting alpha emitters was investigated. The results show that low readout noise is essential for the detection of radioluminescence, as it allows short exposure times to be used. The ICCD camera was found to perform slightly better than the EMCCD camera in the field, while both enable the detection of MBq level alpha activities in 100 s in the Lest configuration (camera target distance 0.5 m). Overall, the cameras and techniques used in this study are shown to be effective in defecting alpha emitters in a standard glovebox. This technology can be applied to nuclear security, safely and safeguards, when stand off defection of alpha emitters is required. (C) 2015 Elsevier B.V. All rights reserved,