Performance of a tracking device based on the GEM scintillation

A tracking device based on gas electron multiplier scintillation using a high-resolution cooled charge-coupled device (CCD) camera was developed. The CCD is sensitive to the 400-1000 nm band, and standard glass photographic lenses are used. The active gas is an Ar-CF/sub 4/ mixture. The prototype detector is described and images of single alpha tracks are presented. The light yield and detector performance for several other gaseous mixtures, such as /sup 4/He-CF/sub 4/, are also investigated.