Precision tunable resonant microwave cavity

Claim 1

Apparatus for ions impressing microwave energy on an ionizable gas to produce a plasma which serves as a source of ions, said apparatus comprising: a cylindrical metal chamber having first and second endwalls; a capsule of ionizable vapor disposed in said first endwall; a tuning wall slidably disposed in said chamber between said endwalls; a plurality of threaded rods attached to said tuning wall and extending through said second endwall in threaded engagement with respective rotatable bushings in said second wall; a plurality of gears with each gear carried on respective one of each of said plurality of threaded rods and meshing with a common gear rotatably supported on said second endwall; common gear driving means for rotating said common gear and, consequently, said rotatable bushings to position said tuning wall; a spherical pivot joint disposed in the cylindrical wall of said cylindrical chamber; a tube having one end retained in said spherical joint and extending outwardly from said chamber; a coaxial probe having a coupling tip position in said chamber between said first endwall and said tuning wall and slidably extending through said tube for connection to a source of microwave energy; means for slidably positioning said coaxial probe in said tube whereby said coupling tip is moveable toward and away from the center axis of said cylindrical metal chamber, said tube being pivotable in said spherical pivot joint within an imaginary cone, the apex of which is at the center of the spherical joint thereby allowing positioning of said coupling tip at a desired location.