Patent ID: 7847232

Claim:
A photomultiplier tube comprising: a vacuum vessel having a faceplate constituting one end and a stem constituting another end, the stem being made from an insulating material and having a first surface, a second surface that opposes the first surface, and a peripheral section that connects the first surface and the second surface; a photocathode that converts incident light incident through the faceplate to electrons; an electron multiplying section that multiplies the electrons emitted from the photocathode, the electron multiplying section including an electrode-layered unit in which a plurality of electrodes including dynodes are stacked in a plurality of stages, the first surface of the stem opposing the electrode-layered unit; an electron detecting section that transmits output signals in response to electrons from the electron multiplying section, wherein the photocathode, the electron multiplying section, and the electron detecting section are provided within the vacuum vessel; a tubular member that surrounds the peripheral section; and an extending section that extends from the tubular member along one of the first surface and the second surface of the stem, each of the first and second surfaces of the stem having an outer circumferential region adjacent to the tubular member, the extending section having a portion covering the outer circumferential region, the portion being formed with openings; and a plurality of potential applying pins penetrate the openings and is fixed to the stem, the plurality of potential applying pins applying potentials to the electrode-layered unit.