Magnetic deflection system for a high-power electron beam
AssigneeLeybold Durferrit GmbH
InventorsMatthias Blum, Josef Heimerl, Martin Bahr, Volker Bauer
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Abstract
A magnetic deflection system for a high-power electron beam with an expanding cross-section area is used for melting or vaporizing metallic materials. Saddle coils are provided which open in a direction of expansion of the electron beam. With the aid of these saddle coils large deflection speeds of the electron beam are obtained with small imaging errors and large deflection angles.
Claims12
A system for controlled magnetic deflection of an electron beam having an expanding cross-sectional area for melting or vaporizing of material in a crucible, comprising:
- a rotationally symmetrical yoke of predetermined shape with an inner jacket surface and an outer jacket surface, wherein a distance from an axis of symmetry of the yoke to the inner jacket surface, d(z)/2, increases in a predetermined direction;
- and
- a saddle coil wound on the yoke having a shape corresponding to the shape of the rotationally symmetrical yoke for deflecting said electron beam within said crucible,
- whereby said electron beam is deflected by a magnetic field generated in said saddle coil to traverse a surface of said material.
A system for controlled magnetic deflection of an electron beam having an expanding cross-sectional area for melting or vaporizing of material in a crucible, comprising:
- a rotationally symmetrical yoke of predetermined shape with an inner jacket surface and an outer jacket surface, wherein a distance from an axis of symmetry of the yoke to the inner jacket surface, d(z)/2, increases in a predetermined direction;
- and
- a saddle coil wound on the yoke having a shape corresponding to the shape of the rotationally symmetrical yoke for deflecting said electron beam within said crucible,
- said yoke inner jacket surface diameter d(z) is determined as a function of a longitudinal distance "z" measured along the axis of symmetry according to the equation:
- ##EQU2## wherein Y.sub.o, m, z.sub.o, and z.sub.w respectively correspond to a measure of a yoke inlet opening, the tangent of a measure of maximum outlet angle, an axial position of a center of curvature and a measure of the degree of curvature,
- whereby said electronic beam is deflected by a magnetic field generated in said saddle coil to traverse a surface of said material.
A system for controlled magnetic deflection of an electron beam having an expanding cross-sectional area for melting or vaporizing of material in a crucible, comprising:
- a rotationally symmetrical yoke of predetermined shape with an inner jacket surface and an outer jacket surface, wherein a distance from an axis of symmetry of the yoke to the inner jacket surface, d(z)/2, increases in a predetermined direction;
- a saddle coil wound on the yoke having a shape corresponding to the shape of the rotationally symmetrical yoke for deflecting said electron beam within said crucible,
- an election beam gun for generating said electron beam;
- and
- two magnetic lenses provided between the electron beam gun and the yoke cooperatingly disposed with the saddle coil,
- whereby said electronic beam is deflected by a magnetic field generated in said saddle coil to traverse a surface of said material.
Dependencies are inferred from the claim text.