Photomultiplier having cascaded microchannel plates, and method for fabrication

An MCP photomultiplier tube comprising:

• a photocathode for receiving photons in a pattern and freeing electrons in response;
• a stack of plural cascaded microchannel plates (MCP's) for receiving said electrons from said photocathode and successively multiplying said electrons by secondary emission of electrons to provide a shower of electrons in a pattern replicating said photons, each of said microchannel plates including a respective pair of opposite facial electrodes for receiving and distributing across the respective microchannel plate an electrostatic charge;
• an anode for receiving said shower of electrons from said microchannel plates and providing a signal current in response;
• and
• electrical connection means for electrically connecting at least one of said plural microchannel plates individually to an electrical power supply,
• wherein said electrical connection means includes said one microchannel plate including a facial surface carrying a portion of each of said pair of electrodes for said one microchannel plate, and a housing with provision to make electrical contact with each of said electrode portions on said facial surface.

An MCP photomultiplier tube including plural microchannel plates cascaded to provide an electron multiplication, said photomultiplier tube comprising:

• a photocathode for receiving photons and releasing electrons in response;
• an anode for receiving said electrons from said photocathode to provide a current indicative of said photon receipt;
• a stack of cascaded microchannel plates disposed to receive said electrons from said photocathode and to release a proportionate shower of secondary emission electrons upon said anode;
• an electrical power supply for powering said photomultiplier tube by maintaining an electrostatic potential from said photocathode across said stack of cascaded microchannel plates and to said anode;
• said stack of cascaded microchannel plates including a high-output microchannel plate having a pair of opposite faces each carrying a corresponding one of a pair of conductive electrodes for said high-output microchannel plate;
• said photomultiplier tube including electrical connection structure for individually connecting said pair of electrodes of said high-output microchannel plate with said electrical power supply,
• wherein said photomultiplier tube includes a housing which provides said individual electrical connection to said high-output microchannel plate;
• wherein said housing includes a pair of shoulders each carrying one of a pair of electrical connections for said high-output microchannel plate, said high-output microchannel plate resting upon said pair of shoulders to respectively connect said pair of electrodes electrically with said pair of connections on said pair of shoulders of said housing.

A method of making a microchannel plate, said method including the steps of:

• providing a perforate substrate having a pair of opposite faces and defining plural microchannels therethrough;
• forming a first electrically conductive electrode on one of said opposite faces;
• forming a second electrically conductive electrode on the other of said opposite faces;
• and
• wrapping a portion of said second electrode around an edge of said substrate to reside on said one opposite face.

A method of making a photomultiplier tube having a high-output microchannel plate, said method comprising the steps of:

• stacking said high-output microchannel plate in heat-transfer relation with an adjacent comparatively lower output microchannel plate;
• associating said adjacent lower-output microchannel plate in heat-transfer relation with a housing of said photomultiplier tube;
• and
• employing said lower-output microchannel plate as a heat-conduction member to transfer electrical resistive heat from said high-output microchannel plate to said housing.

A method of making a photomultiplier tube having a unitary ceramic body, said method comprising the steps of:

• forming said unitary ceramic body in a disk-like form with a pair of opposite faces, one face of which defines a shallow recess with a central planar surface and at least a pair of step-like shoulders extending circumferentially of said central planar surface, the outer one of said step-like shoulders being circumferentially continuous;
• disposing an anode on said central planar surface;
• disposing a microchannel plate on one of said step-like shoulders spaced from said anode;
• sealingly associating a window member with said body at said outer circumferentially continuous step-like shoulder to define a vacuum chamber within said recess;
• and
• carrying a photocathode upon said window member within said vacuum chamber.