Bendix M306 Continuous Resistance Strip Electron Multiplier, an ultraviolet detector representative of those used on the OSO-F satellite. Utilizes an open cathode magnetic electron multiplier design that does not need to be enclosed in a glass or other insulating envelope since the vacuum required for its operation is supplied by the lack of atmosphere in Earth orbit. A UV photon striking the surface of the cathode at the entrance grid of the device results in the release of one or more electrons. The first of a series of permanent magnets then directs the emitted electrons onto a strip of specially coated glass. This results in the release of a large number of secondary electrons. Repetition of this process leads to a cascade of charge. The current gain can be as high as 10 million fold. The detector was transferred to NASM by NASA (GSFC) in 1988.