Pole insert for cyclotron

Patent metadata

Field	Value
Publication number	US-10064264-B2
Application number	US-201715594525-A
Country	US
Kind code	B2
Filing date	May 12, 2017
Priority date	May 13, 2016
Publication date	Aug 28, 2018
Grant date	Aug 28, 2018

Abstract

The present disclosure relates to a magnet pole for an isochronous sector-focused cyclotron having hill and valley sectors alternatively distributed around a central axis, Z, each hill sector having an upper surface bounded by four edges: an upper peripheral edge, an upper central edge, a first and a second upper lateral edges. The upper surface of at least one hill sector may further include: a recess extending over a length between a proximal end and a distal end along a longitudinal axis intersecting the upper peripheral edge and the upper central edge. The recess may be separate from the first and second upper lateral edges over at least 80% of its length, and a pole insert having a geometry fitting in the recess may be positioned in, and reversibly coupled to the recess.

First claim

The invention claimed is:

1. A magnet pole for use in a cyclotron, comprising:
at least three hill sectors, each associated with a magnetic field; and
a same number of valley sectors alternatively distributed around a central axis, where each valley sector is associated with a magnetic field, where the magnetic fields of the hill sectors are stronger than the magnetic fields of the valley sectors,
each hill sector comprising an upper surface defined by:
an upper peripheral edge, said upper peripheral edge being bounded by a first and a second upper distal ends, and being defined as the edge of the upper surface located furthest from the central axis,
an upper central edge, said upper central edge being bounded by a first and a second upper proximal ends and being defined as the edge of the upper surface located closest from the central axis,
a first upper lateral edge connecting the first upper distal end and first upper proximal end, and
a second upper lateral edge connecting the second upper distal end and second upper proximal end,

wherein the upper surface of at least one hill sector further comprises:
a recess extending over a length between a proximal end and a distal end along a longitudinal axis intersecting the upper peripheral edge and the upper central edge, said recess being separate from the first and second upper lateral edges over at least 80% of its length, and
a pole insert having a geometry fitting in said recess and being positioned in, and reversibly coupled to, said recess.

2. A magnet pole according to claim 1 , wherein the recess extends to the upper peripheral edge.

3. A magnet pole according to claim 1 , wherein the recess extends to the upper central edge.

4. A magnet pole according to claim 1 , wherein the pole insert includes comprises a portion having a prismatic geometry.

5. A magnet pole according to claim 4 , wherein a cross section normal to the longitudinal axis of the prismatic portion of the pole insert is trapezoidal, having lateral surfaces converging from the upper surface.

6. A magnet pole according to claim 4 , wherein the pole insert has a proximal portion adjacent to the prismatic portion, wherein an area of a cross-section normal to the longitudinal axis of the proximal portion decreases towards the proximal end of the pole insert, comprises the whole upper central edge, and is flush with the first and second lateral edges of the corresponding hill sector.

7. A magnet pole according to claim 1 , wherein the pole insert has a length measured parallel to the longitudinal axis and a width measured normal to said longitudinal axis, and comprises an insert upper surface and a first and second insert lateral surfaces, at least one of the lateral surfaces being structured with a succession of recesses and protrusions.

8. A magnet pole according to claim 7 , wherein the recesses and protrusions extend normal to the longitudinal axis over the whole width of the pole insert.

9. A magnet pole according claim 7 , wherein at least a portion of the recesses and protrusions are grooves being transverse or parallel to the longitudinal axis and extending along a straight, curved, or broken line.

10. A magnet pole according claim 7 , wherein at least a portion of the recesses and protrusions are holes being blind holes or through holes.

11. A magnet pole according to claim 1 , wherein each hill sector has an average height measured parallel to the central axis between the upper surface and the valley sector, and wherein the pole insert has a height measured parallel to the central axis and being between 20% and 80% of the height of a hill sector.

12. A magnet pole according claim 11 , wherein the pole insert has a height being between 30% and 70% of the height of a hill sector.

13. A magnet pole according claim 12 , wherein the pole insert has a height being between 40% and 60% of the height of a hill sector.

14. A magnet pole according to claim 1 , wherein each hill sector has an azimuthal length measured between the first and a second upper distal ends, and wherein the pole insert has a width not more than 15% of the azimuthal length of a hill sector.

15. A magnet pole according claim 14 , wherein the pole insert has a width not more than 10% of the azimuthal length of a hill sector.

16. A magnet pole according claim 14 , wherein the pole insert has a width not more than 5% of the azimuthal length of a hill sector.

17. A magnet pole according to claim 1 , wherein each valley sector comprises a bottom surface, and each hill sector comprises first and second lateral surfaces, defined as surfaces extending transversally from the first and second upper lateral edges, to the bottom surfaces of corresponding valley sectors located on either sides of a hill sector, said first and second upper lateral edges preferably forming a chamfer at the level of the first and second lateral edges, respectively.

18. A magnet pole according to claim 1 , wherein the first and second lateral edges are straight lines.

19. A magnet pole according to claim 1 , wherein the longitudinal axis intersects the upper peripheral edge at a point of the upper peripheral edge located at equal distance ±10% from the first and second upper distal ends.

Assignees

• Ion Beam Appl Sa
• Ion Beam Appl Sa

Inventors

• Abs Michel
• Zaremba Szymon

Classifications

• H05H13/005

  Cyclotrons · CPC title

• H05H2007/002

  for modifying beam trajectory, e.g. gantries · CPC title

• H05H2007/043

  for beam focusing · CPC title

• H05H13/08

  Alternating-gradient magnetic resonance accelerators · CPC title

• H01F3/10

  Composite arrangements of magnetic circuits · CPC title