Patent ID: 7238928

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 which is used for extracting 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 plurality of stem pins insertedly mounted in the stem and leading to an exterior of the sealed container from inside the sealed container and being electrically connected to the anode and the electron multiplier unit, wherein the stem pins are passed through stem pin passing portions of both an inner surface and an outer surface of the stem and joined to the base member, and each of the stem pin passing portions of both the inner surface and the outer surface comprises a recess through which the stem pin is passed with the recess having a bottom surface and the base member forming the bottom surface of the recess.