Future UV detectors for space applications

We review the basic concepts of UV detectors and discuss why astronomers and planetary geologists place requirements of the detectors to be both UV sensitive and yet visible blind. This visible-blind requirement means that although CCD (and CMOS) based cameras can be quite efficient in the UV (approximately 40%), when filters are applied to knock out the necessary visible contribution, the effective CCD sensitivity is reduced significantly. We review several detector concepts from wide band-gap semi-conductors (primarily GaN-based) to Si-based (CCD and CMOS) and low temperature detectors (e.g., transmission edge sensors [TESs], superconducting Tunnel Junctions (STJs), and metallic magnetic calorimeters (MMCs). We conclude a new mission that would use a GaN photo-cathode camera for the UV low light level applications.