Detector for narrow band ultra violet radiation

摘要

The sampling mirror (12) scans in a circle around the axis of a drive motor (14). The beam of light is deflected downwards onto the input window (24) of the photomultiplier tube (18), via a telescopic focusing system (16). The tube has a tungsten cathode (20) and is filled with an inert gas. The tube window is covered by a film of filter material. The material is a polymer which passes ultra violet light in a waveband between 232 and 275 nanometres. The filter characteristic has "sharp" cut-off edges.