A 16 mm active diameter photomultiplier tube (PMT) having an electron-bombarded silicon avalanche diode electron multiplier is shown to have promise as a replacement for PMTs with conventional discrete dynode or channel electron multipliers. Any type of conventional photocathode, e.g. uv-sensitive, bialkali or multialkali types, as well as negative electron affinity GaAs types can be used. The full potential of the high detective quantum efficiency of the GaAs cathode can be realized for the first time in a photoelectronic detector because of the nearly complete utilization of the photoelectrons. Key performance characteristics are gain to about 1E6 e/e, linear dynamic range for dc operation to about 1E6, insensitivity to strong magnetic fields, and a counting efficiency of about 80%.