Patent ID: 7132639

Claim:
A photomultiplier comprising: a photoelectric surface disposed inside a sealed container, which is put in a vacuum state, and converting incident light made incident through a light receiving plate into electrons, which forms an end portion at one side of the sealed container; an electron multiplier unit disposed inside the sealed container and multiplying electrons emitted from the photoelectric surface; an anode disposed inside the sealed container and used for taking out the electrons multiplied by the electron multiplier unit as an output signal; a stem forming an end portion at the other side of the sealed container and having a base member, with an insulating property, and a holding member, having a melting point higher than that of the base member and being joined to one of an inner surface and an outer surface of the base member; and a plurality of stem pins insertedly mounted in the stem and leading to the exterior from inside the sealed container and electrically connected to the anode and the electron multiplier unit, wherein the stem pins are passed through and joined to the base member, and the electron multiplier unit and the anode are layered on the inner surface of the stem, and the base member and the holding member, and the base member and the stem pins are respectively joined by fusion by the melting of the base member, and a base member seep portion, into which the base member seeps upon melting, is disposed in at least one of the holding member and the base member.