Patent ID: 7786445

Claim:
A multi-anode type photomultiplier tube comprising: a faceplate made from glass and having a first main surface and a second main surface opposite to the first main surface; a hollow side tube made from glass and joined to the first main surface of the faceplate, the side tube extending along a tube axis that is substantially perpendicular to the faceplate; a photocathode that emits photoelectrons according to light incident on the faceplate, the photocathode being provided in an area inside the side tube on the first main surface of the faceplate; and a plurality of electron multiplying sections and a plurality of anode electrodes, which are provided inside the side tube and which correspond to a plurality of areas on the photocathode, the side tube including a first portion and a second portion arranged along the tube axis, the second portion being connected at its one edge along the tube axis to the first portion and being connected at its other edge along the tube axis to the first main surface of the face plate, the first portion extending along the tube axis by a first length, the first portion having a substantially quadrangular prismatic hollow shape, the first portion having a substantially rectangular cross section substantially perpendicular to the tube axis, the cross-section of the first portion having a first size, the face plate having a substantially quadrangular shape and having a second size of cross section substantially perpendicular to the tube axis, the second size being greater than the first size, the second portion extending along the tube axis by a second length, the second length being less than the first length, the second portion having a substantially rectangular cross-section substantially perpendicular to the tube axis, the cross-section of the second portion having the first size at its one edge and having the second size at its other edge, the photocathode being provided inside the second portion, and the plurality of electron multiplying sections and the plurality of anode electrodes being provided inside the first portion of the side tube.