Abstract: Optical detection method of α surface contamination based on air Radioluminescence was one of the active area of research since its first demonstration at the beginning of this century. Compared to other kinds of α surface contamination measurement methods, the optical detection method of α surface contamination has the following advantages: it can realize non-contact α surface contamination measurement, it can effectively measure non-flat surface α contamination, and finally it can effectively reduce the risk of surface contamination. But on the other hand, affected by low emission yield of air Radioluminescence from α particle energy deposition, the detection limit of optical detection method of α surface contamination is too high compared with other kinds of α surface contamination methods. In this paper we presented a prototype instrument for measurement of α surface contamination. The instrument is based on optical detection of air Radioluminescence from α radiation, and work in telescope scanning mode. Primary performance testing results show that, the sensitivity of the prototype instrument is 2.63 s^-1/kBq, and the MDA is 1.0 kBq at 1 m distance from object lens and 10 s measurement time. Field experiment shows that the prototype instrument can also accurately measure space distribution of α surface contamination.

Key words: α surface contamination, air radioluminescence, optical detection