Patent ID: 7880385

Claim:
A photomultiplier, comprising: a housing whose inside is maintained in a vacuum state, said housing including an insulating plate which constitutes a part of said housing and has a device mount surface; a photocathode, accommodated in said housing, emitting electrons to the inside of said housing in response to light taken in via said housing; an electron-multiplier section, accommodated in said housing, having dynode channels respectively defined by spaces each extending along an electron traveling direction; and anodes, accommodated in said housing, taking out, as signals, electrons having reached among electrons cascade-multiplied in said electron-multiplier section, said anodes being constituted by a plurality of channel electrodes which are provided to respectively correspond to the dynode channels in said electron-multiplier section, wherein both of said electron-multiplier section and said anode are directly fixed on the same device mount surface of said insulating plate, wherein each of said channel electrodes includes a main body directly fixed on an area of the device mount surface excluding an area on which said electron-multiplier section is directly fixed, and a protruding portion which extends along a direction parallel to the device mount surface of said insulating plate and which has one end located in the space defining the associated dynode channel and the other end supported by said main body while being separated from said insulating plate so as to be located outside of the space defining the associated dynode channel, and wherein, in the direction parallel to the device mount surface of said insulating plate, a length of the portion of said protruding portion which is located in the space defining the associated dynode channel is shorter than that of the portion of said protruding portion which is located outside of the space defining the associated dynode channel.