Long life, low noise proximity focused image intensifiers

Summary form only given. The Night Vision Goggle System, recently developed by the Night Vision Laboratory and the International Telephone and Telegraph Company (ITT), has been very successfully demonstrated in various night operations such as driving, flying and other close-up operations. The light amplifier is a proximity focused image intensifier with a microchannel plate (MCP) as the gain mechanism. A major problem in development life, caused by a decrease of the cathode sensitivity due to ion feedback from the MCP. In addition, ions feedback is responsible for the very bright scintillations at the output phosphor screen giving the output image a degraded noisy appearance especially at very low light levels. At the Night Vision Laboratory, a technique was developed to coat the input of the MCP with a very thin film of Al₂O₃, preventing ion feedback but allowing electrons with energy greater than 800 ev to pass with practically no loss. This increased the operational lifetime of the intensifier by more than a factor 10. By modifying the processing of the MCP in the tube and some redesign of the tube structure other performance characteristics were also improved.