Test system for measuring sensitivity of image intensifiers - uses chopped light at input and synchronised photomultiplier at output

摘要

The cathode sensitivity tester comprises a light source (4) with grey filter (3) and chopper disc (12). The image-intensifier tube under test is placed between an outlet aperture (2) and an object lens (5) which focusses the output of the tube onto a photo-multiplier (7) via a three-stage image intensifier (6). The multiplier (7) via a three-stage image intensifier (6). The multiplier is synchronised to the chopper. A defined sequence of light flashes of a predetermined colour temp. are applied to the image intensifier tube under test. With a cathode sensitivity of 500 mu A/Lumen for example, exactly one electron per flash is produced. The level and number of light flashes appearing at the measuring surface are recorded. The total number of primary electrons emitted is divided by the number of input flashes and multiplied by 500 mu A/Lumen to obtain the sensitivity.