Method and apparatus for deflecting charged particles
AssigneeNissin Electric Co., Ltd.
InventorsMasahiko Aoki, Masayasu Tanjyo
Life of this patent
Estimating the term…
Abstract
A large-area ion beam having a one-directionally long section is generated in a magnetically shielded ion source. The ion beam is bent evenly to form a large center angle of about 90 degrees in the direction of the short side by a window/frame type magnet having a large gap and having left and right frames each wound with a plurality of coils. Then, the ion beam is made to pass through a slit plate having a one-directionally long opening so that unnecessary ions are removed. The ion beam is then radiated onto a subject which makes a translational motion in the direction of the short side of the beam.
Claims14
An apparatus for deflecting charged particles, comprising:
- an ion source having an ion drawing outlet long in a certain direction for generating a belt-like ion beam;
- a magnet comprising a yoke of a ferromagnetic material having a rectangular section and being curved in its longitudinal direction, a plurality of coils wound on a curved inner frame of said yoke so as to be parallel with a direction of movement of the beam, and a plurality of coils wound on a curved outer frame of said yoke so as to be parallel with the direction of movement of the beam;
- a slit plate having a long hole long in the same direction as the longitudinal direction of said ion source and provided on a beam locus of the beam and in posterior to said magnet;
- and
- a mechanism for holding a subject so that said subject makes a translational motion in a direction of a short side of a section of the beam;
- wherein magnetic field B.sub.y substantially uniform in the same direction as the longitudinal direction of the ion source is generated in the inside of said yoke by adjustment of currents in said plurality of coils, so that a belt-like ion beam having a section long in a certain direction is emitted from said ion source, made to pass through said yoke so as to be curved in the direction of the short side of the section of the beam by the longitudinal magnetic field, made to pass through the long hole of the slit plate to remove unnecessary ions and radiated onto the subject.
A method for deflecting charged particles using an apparatus comprising:
- an ion source having an ion drawing outlet long in a certain direction for generating a belt-like ion beam;
- a magnet comprising a yoke of a ferromagnetic material having a rectangular section and being curved in its longitudinal direction, a plurality of coils wound on a curved inner frame of said yoke so as to be parallel with a direction of movement of the beam, and a plurality of coils wound on a curved outer frame of said yoke so as to be parallel with the direction of movement of the beam;
- a slit plate having a long hole long in the same direction as the longitudinal direction of said ion source and provided on a beam locus of the beam and in posterior to said magnet;
- and a mechanism for holding a subject so that said subject makes a translational motion in a direction of a short side of a section of the beam;
- said method comprising the steps of:
- generating magnetic field B.sub.y substantially uniform in the same direction as the longitudinal direction of the ion source in the inside of said yoke by adjustment of currents in said plurality of coils, so that a belt-like ion beam having a section long in a certain direction is emitted from said ion source;
- passing said ion beam through said yoke so as to be curved in the direction of the short side of the section of the beam by the longitudinal magnetic field;
- and
- passing said ion beam through the long hole of the slit plate to remove unnecessary ions and radiated onto the subject.
Dependencies are inferred from the claim text.