US 4,058,748 AGranted

Microwave discharge ion source

AssigneeHitachi, Ltd.

InventorsNoriyuki Sakudo, Katsumi Tokiguchi, Ichiro Kanomata

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Abstract

An ion source for emitting an efficient radiation of ion beam having a rectangular cross section includes a set of parallel electrodes to which a microwave power is supplied to generate a microwave electric field in an electrode gap. A DC magnetic field is applied in a direction along the opposing surfaces of the electrodes to provide a microwave discharge in the electrode gap in cooperation with the microwave electric field crossing therewith. The electrode gap or discharge space has a rectangular cross section perpendicular to a direction along which ions produced by the microwave discharge are extracted as an ion beam with a side of the cross section corresponding to the distance between the electrodes being shorter than its side crossing therewith. This allows the efficient generation of the ion beam having the rectangular cross section through one or more extraction electrodes which include rectangular slits corresponding in pattern to the above-mentioned cross section.

Claims13

Dependent claims

A microwave discharge ion source comprising a set of conductive members for producing a microwave electric field therebetween, means for generating a magnetic field in a direction perpendicular to said microwave electric field, means for introducing a sample gas or vapor, at least one extraction electrode for taking ions out of a plasma produced by a microwave discharge which occurs in the atmosphere of the introduced sample gas or vapor in cooperation with said microwave electric field and said magnetic field, and a vacuum-sealing insulator provided at an end portion opposite to the end portion at which said extraction electrode is provided, wherein said set of conductive members are a set of electrodes having their surfaces arranged in opposing and substantially parallel relationship;

a discharge space defined in the proximity of an electrode gap between said electrodes has a cross section substantially rectangular in a plane perpendicular to a direction along which the ions are extracted;
said extraction electrode is provided with a slit having substantially the same pattern as that of said rectangular cross section, an ion beam having a rectangular cross section being extracted through said slit;
and said vacuum-sealing insulator is made of a conductor material at a position at which it comes into contact with said electrodes, said conductor material being vacuum-tightly attached to said vacuum-sealing insulator.

Dependencies are inferred from the claim text.