Transmission Secondary Electron Multiplication for High-Speed Pulse Counting

A new type of high-speed electron multiplier employing transmission secondary electron emission from thin insulating films is described. Electrons from a photosurface are multiplied in a series of plane-parallel dynodes consisting of a thin scattering layer of a heavy metal followed by a layer of a pure crystalline insulating material of high secondary emission yield. The characteristics of such dynodes are described, and the dc and pulse performance of an experimental seven-stage device employing this principle is presented.