Electron Multipliers Utilizing Continuous Strip Surfaces

Thin films of semiconducting materials with secondary electron emission ratios greater than one have been used for some years in the Bendix crossed electric and magnetic field electron multiplier for ion detection. In these devices the electric field to accelerate the electrons is established by the potential gradient created by external current flowing through the resistive strip. A low background counting rate, insensitivity to radiation in the visible and near ultraviolet, and stability on exposure to atmospheric gases are properties which permit this device to have interesting photon detection applications in the extreme ultraviolet in dynamic vacuum systems and outer space environment. A new form of electron multiplier utilizing continuous thin film surfaces, but not requiring a magnetic field, has been developed. Small diameter tubes (a few mils I.D.) coated on the inside surface give gains up to 106. This "channel" multiplier has been operated singly as a miniature electron or photon detector, and in arrays in image intensifiers. The principle of operation and some applications of these channel amplifiers will be discussed.