Deflection electromagnet for a charged particle device

• US 5,111,173 A
• Filed: 09/07/1990
• Issued: 05/05/1992
• Est. Priority Date: 03/27/1990
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Matsuda, Tetsuya, Ushijima, Toshie, Yamada, Tadatoshi, Yamamoto, Shunji
• Primary Examiner(s): Picard, Leo P.
• Assistant Examiner(s): Barrera, Ramon M.
• Application Number:
  US07/578,790
• Time in Patent Office: 606 Days
• Field of Search: 335/210, 335/213, 335/299, 335/216, 328/235
• US Class Current: 335/216
• CPC Class Codes: H05H 7/04 Magnet systems , e.g. undulators, wigglers free-electron laser H01S3/0903; Energisation thereof

Abstract

Semicircular superconducting deflection magnets for deflecting electron beams along a semiconductor orbit. The magnet 1 comprises a pair of race-track shaped main coils 2 and 3 disposed symmetrically with respect to the plane of the orbit S. Each one of the main coils 2 and 3 is divided into two parts 21 and 22 or 31 and 32, the end portions 21a and 22a or 31a and 32a being displaced from each other in the direction of the orbit S, so that the magnetomotive force thereof is distributed evenly along the orbit S (FIGS. 12 through 14). According to another aspect, rectangular cancellation coils 25, 26, 35, and 36 are provided at the end portions 21a, 22a, 31a, and 32a, respectively, of the coil parts 21, 22, 31, and 32, such that the magnetomotive force of each one of the end portions is cancelled by the magnetomotive force of the adjacent parallel running side of a cancellation coil (FIGS. 21 through 23). According to still another aspect, sextupole correction coils 5 are disposed near the end portions 2a of the main coils 2 along the orbit S.

Claims

1. A deflection magnet for deflecting a charged particle beam along a semicircular orbit, said deflection magnet comprising:

an upper and a lower race-track shaped superconducting coil bent into a semicircular form along the semicircular orbit divided into at least two coil parts through a plane perpendicular to the plane of the orbit of the charged particle beam and disposed symmetrically with respect to the plane of the orbit of the charged particle beam, said race-track shaped upper and lower coils each including radially inner and outer semicircular branches running parallel to the semicircular orbit and end portions bridging the radially inner and outer branches;

wherein each one of the end portions of the upper and lower coils is divided into at least two parts which are displaced from each other in a plane parallel to the plane of the orbit.

4. A deflection magnet as claimed in claim 1, wherein each one of said main coils is divided at least into two coil parts, the end portion of each one of the coil parts being provided with a cancellation coil having a side running parallel and adjacent to the end portion.

2. A deflection magnet for deflecting a charged particle beam along a semicircular orbit, said deflection magnet comprising:

race-track shaped main coils bent into a semicircular form along the semicircular orbit, and disposed symmetrically with respect to the plane of the orbit of the charged particle beam, said race-track shaped main coils including end portions bridging radially inner and outer semicircular branches thereof running parallel to the semicircular orbit; and

rectangular cancellation coils each provided at one of said end portions of the main coils, each cancellation coil having a side running parallel and adjacent to one of the end portions of the main coils, the plane of each one of the cancellation coils forming a substantial angle to the plane of the orbit, wherein the direction and magnitude of current flowing in each one of the cancellation coils is such that the magnetomotive force of the current flowing through the side of each cancellation coil parallel and adjacent to an end portion of the main coils is equal in magnitude and opposite in direction to the magnetomotive force of a current flowing through the end portion.

3. A deflection magnet as claimed in claim 2, wherein the plane of each one of the cancellation coils form a right angle to the plane of the orbit.

8. A deflection magnet as claimed in claim 2 wherein the main coils are divided into at least two parts through a plane perpendicular to the plane of orbit of the charged particle beam.

9. A deflection magnet as claimed in claim 2 wherein the main coils are divided into at least two parts through a plane parallel to the plane of orbit of the charged particle beam.

5. A deflection magnet for deflecting a charged particle beam along a semicircular orbit, said deflection magnet comprising:

race-track shaped main coils bent into a semicircular form along the semicircular orbit and disposed symmetrically with respect to the plane of the orbit of the charged particle beam, said race-track shaped main coils including end portions bridging radially inner and outer semicircular branches thereof running parallel to the semicircular orbit; and

multipolar correction coils each disposed near one of the end portions of the main coils along the orbit of the charged particle, such that an integral of a multipolar magnetic field component, generated by the main coils and the correction coils, along the orbit of the charged particle beam vanishes.

6. A deflection magnet as claimed in claim 5, wherein said multipolar correction coils comprise sextupole correction coils.

7. A deflection magnet as claimed in claim 5 wherein the main coils are divided through a plane parallel to the plane of the orbit of the charged particle beam.

10. A deflection magnet for deflecting a charged particle beam along a semicircular orbit, said deflection magnet comprising:

upper and lower race-track shaped superconducting coils bent into semicircular form along the semicircular orbit and disposed symmetrically with respect to the plane of the orbit of the charged particle beam, said race-track shaped upper and lower coils each including radially inner and outer semicircular branches running parallel to the semicircular orbit and end portions bridging the radially inner and outer branches;

wherein each one of the end portions of the upper and lower coils is divided into at least two layers disposed in a stepped configuration.