High speed 0.53 micron hybrid photomultiplier tube

This paper describes the development and performance of an electron beam-semiconductor hybrid photo multiplier tube for gigahertz laser communications. The photomultiplier tube consists of a photocathode, with peak sensitivity at 0.53 µm corresponding to light from a Nd-YAG frequency doubled laser source, and a fast silicon diode in parallel proximity to the photocathode. The diode is mounted on a specially designed 50 ohm coaxial feedthrough at the base of the tube. The low-noise property of the detector is preserved by transferring the processed photocathode through the vacuum system into its final position in the tube. This technique is also necessary to prevent degradation of the diode characteristics during processing. The reverse biased silicon diode acts as the electron multiplier and collector. The bandwidth and S/N considerations for this hybrid photomultiplier tube will be presented. The solutions of the problems associated with the compatibility of the tube components with each other and with the tube processing techniques will be given.