Gradient corrector for cyclotron
AssigneeIon Beam Applications S.A.
InventorsWillem Kleeven, Szymon Zaremba
Life of this patent
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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, and a peripheral surface extending from the upper peripheral edge to a lower peripheral line. The upper peripheral edge of at least one hill sector may further include a concave portion with respect to the central axis defining a recess extending at least partially over a portion of the peripheral surface of the corresponding hill sector.
Claims22
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 comprising a bottom surface, 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,
- said hill sectors and valley sectors being alternatively distributed around a central axis, and
- 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;
- a first lateral surface and a second lateral surface, each 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, thus defining a first and second lower lateral edges as the edges intersecting a lateral surface with an adjacent bottom surface, said first and second lower lateral edges each having a lower distal end located furthest from the central axis;
- and
- a peripheral surface extending from the upper peripheral edge to a lower peripheral line defined as the segment bounded by the lower distal ends of the first and second lower lateral edges,
- wherein the upper peripheral edge of at least one hill sector comprises a concave portion with respect to the central axis defining a recess extending at least partially over a portion of the peripheral surface of a corresponding hill sector.
(canceled)
(canceled)
A cyclotron according to claim 22, wherein the recess has a first and a second recess distal points, said first and second recess distal points being separated from one another by a distance, and wherein a hill gap portion between a pair of hill sectors of the first and second magnet poles has an average height, and wherein the ratio of the average height to the length is between 5 and 100%.
A cyclotron according to claim 22, further comprising a point of extraction located in a hill gap portion between two opposite upper surfaces of hill sectors of the first and second magnet poles, wherein:
- the given path of the particle beam is an outward spiral path cycling about the first central axis until said first point of extraction whence the particle beam is driven out of the cyclotron with a given energy along an extraction path,
- the first recess is located downstream from said point of extraction, and
- the extraction path exits the corresponding hill gap portion by intersecting the recess at an angle between 80° and 100°.
A cyclotron for accelerating a particle beam over a given path within a gap, the cyclotron comprising:
- a first magnet pole and a second magnetic pole, wherein at least one of the first and second magnetic poles comprises:
- at least three hill sectors, each associated with a magnetic field;
- and
- a same number of valley sectors comprising a bottom surface, 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,
- said hill sectors and valley sectors being alternatively distributed around a first central axis, and
- each hill sector comprising:
- an upper surface defined by an upper peripheral edge bounded by a first and a second upper distal ends and being defined as the edge of the upper surface located furthest from the first central axis, an upper central edge bounded by a first and a second upper proximal ends and being defined as the edge of the upper surface located closest from the first 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;
- a first lateral surface and a second lateral surface, each 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, thus defining a first and second lower lateral edges as the edges intersecting a lateral surface with an adjacent bottom surface, said first and second lower lateral edges each having a lower distal end located furthest from the first central axis;
- and
- a peripheral surface extending from the upper peripheral edge to a lower peripheral line defined as the segment bounded by the lower distal ends of the first and second lower lateral edges,
- wherein the upper peripheral edge of at least one hill sector comprises a concave portion with respect to the first central axis defining a first recess extending at least partially over a portion of the peripheral surface of a corresponding hill sector.
Dependencies are inferred from the claim text.