Patent ID: 8242694

Claim:
A photomultiplier comprising: an enclosure having an inner wall defining an internal space that is kept in a vacuum state, said inner wall including a flat part; a photocathode, accommodated in said enclosure, emitting photoelectrons to the inner space of said enclosure in response to light captured through said enclosure; an electron multiplier section, arranged on the flat part of said inner wall, for multiplying in a cascading manner the photoelectrons emitted from said photocathode, said electron multiplier section having a structure making electrons multiplied in the cascade manner propagate along the flat part of said inner wall; and an anode, arranged on the flat part on which said electron multiplier section is arranged, for taking out electrons having arrived thereat among the electrons multiplied in said electron multiplier section as a signal, wherein said electron multiplier section and said anode are comprised of a silicon material, wherein said enclosure comprises: a first frame of insulation having a first inner surface, and a first outer surface opposing said first inner surface and exposed to the external of said enclosure; a second frame of insulation having a second inner surface facing said first inner surface, and a second outer surface opposing said second inner surface and exposed to the external of said enclosure; and a side wall frame, provided between said first and second frames, having a form surrounding said electron multiplier section and said anode, said side wall frame being comprised of a silicon material, wherein the flat part of said inner wall is positioned on any one of said first and second inner surfaces of said first and second frames, and wherein said side wall frame, said electron multiplier section and said anode are separated from each other.