Patent ID: 7977878
Filing Date: 2011-07-12
Classification: H01J

Abstract:
1. 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 internal space of said enclosure in response to light captured through said enclosure; an electron multiplier section, arranged on and in direct contact with 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; an anode, arranged on and in direct contact with 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; a photocathode electrode having one end electrically connected to said photocathode, and the other end being exposed to the external of said enclosure; an anode electrode having one end electrically connected to said anode, and the other end being exposed to the external of said enclosure; a first through hole accommodating said photocathode electrode therein and extending along a direction orthogonal to the flat part of said inner wall; and a second through hole accommodating said anode electrode therein and extending along the direction orthogonal to the flat part of said inner wall, wherein said anode is comprised of a silicon material, wherein said enclosure comprises: a lower 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; an upper 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 upper and lower 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 included in any one of said first and second inner surfaces of said lower and upper frames, wherein said first through hole is provided in any one of said lower and upper frames while being apart from said side wall frame, whereby said photocathode electrode accommodated in said first through hole is electrically separated from said side wall frame, and wherein said second through hole is provided in any one of said lower and upper frames while being apart from said side wall frame, whereby said anode electrode accommodated in said second through hole is electrically separated from said side wall frame.