Patent ID: 7902509

Claim:
A photomultiplier tube comprising: a vacuum vessel having a faceplate constituting one end and a stem constituting another end; a photocathode that converts incident light incident through the faceplate to electrons; an electron multiplying section that multiplies the electrons emitted from the photocathode; and 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, wherein the electron multiplying section includes an electrode-layered unit in which electrodes including dynodes that constitute a plurality of channels are stacked in a plurality of stages in a stacking direction; wherein the electron detecting section includes a plurality of anodes that is arranged spaced away from and in confrontation with a last stage electrode of the electrode-layered unit and that is arranged in association with the channels; and wherein the stem is provided with a supporting portion that penetrates through the stem and is fixed to the stem, the supporting portion having a first end face and a second end face opposite the first end face, the last stage electrode being placed on the first end face, and the second end face being exposed to outside of the vacuum vessel.