Patent ID: 7317283
Filing Date: 2008-01-08
Classification: H01J

Abstract:
1. A photomultiplier comprising: a sealed container of which the inside is kept in a vacuum state; a photocathode, accommodated in said sealed container, for emitting photoelectrons to the inside of the sealed container in response to light having a predetermined wavelength; and an electron-multiplying unit accommodated in said sealed container without being in contact with an inner wall of said sealed container, said electron-multiplying unit having: wherein said pair of insulating support members each has one or more protruding portions that extend toward said photocathode and that at least serve as a reference of the arranged position of said focusing electrode, and each of said protruding portions has a fixture structure for fixing said focusing electrode in a state of supporting directly said focusing electrode, and wherein said focusing electrode has a main body defining said through hole, and a flange portion extending from an edge portion of said main body to the tube axis of said sealed container, said flange portion being provided with one or more notched portions to be grasped by a part of each of said insulating support members when the focusing electrode itself is rotated around the tube axis of said sealed container.