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 peripheral edge of a hill sector may be an arc of circle whose center is offset with respect to the central axis, and whose radius, Rh, is not more than 85% of a distance, Lh, from the central axis to a midpoint of the upper peripheral edge. Furthermore, the midpoint may be equidistant to the first and second upper distal ends.

To provide an accelerator that easily provides a space for placing equipment incorporated into an accelerator magnet, and that has a dense region with small turn separations of beams and a sparse region with large turn separations of the beams in different positions in the beam orbit direction. A pair of magnetic poles (8, 9) has a depression structure of a plurality of depression and projection structures, in a position intersecting with a vertical plane (3). A boundary surface (41, 44, 45, 48) between the depression structure (21, 23) placed in a position intersecting with the vertical plane (3) and a projection structure (31, 32, 33, 34) adjacent to the depression structure has unanimously either a projection shape or a depression shape with respect to the vertical plane (3).

To provide an accelerator that easily provides a space for placing equipment incorporated into an accelerator magnet, and that has a dense region with small turn separations of beams and a sparse region with large turn separations of the beams in different positions in the beam orbit direction. A pair of magnetic poles (8, 9) has a depression structure of a plurality of depression and projection structures, in a position intersecting with a vertical plane (3). A boundary surface (41, 44, 45, 48) between the depression structure (21, 23) placed in a position intersecting with the vertical plane (3) and a projection structure (31, 32, 33, 34) adjacent to the depression structure has unanimously either a projection shape or a depression shape with respect to the vertical plane (3).

To provide an accelerator that easily provides a space for placing equipment incorporated into an accelerator magnet, and that has a dense region with small turn separations of beams and a sparse region with large turn separations of the beams in different positions in the beam orbit direction. A pair of magnetic poles (8, 9) has a depression structure of a plurality of depression and projection structures, in a position intersecting with a vertical plane (3). A boundary surface (41, 44, 45, 48) between the depression structure (21, 23) placed in a position intersecting with the vertical plane (3) and a projection structure (31, 32, 33, 34) adjacent to the depression structure has unanimously either a projection shape or a depression shape with respect to the vertical plane (3).

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.

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.

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.

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.

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 peripheral edge of a hill sector may be an arc of circle whose center is offset with respect to the central axis, and whose radius, Rh, is not more than 85% of a distance, Lh, from the central axis to a midpoint of the upper peripheral edge. Furthermore, the midpoint may be equidistant to the first and second upper distal ends.

The present disclosure relates to compact isochronous sector-focused cyclotrons having reduced dimensions and weight compared with state of the art cyclotrons of same energies. In one implementation, a cyclotron may include two pole magnets facing each other in a chamber defined by a yoke having base plates and flux return yokes forming a lateral wall of the chamber. The magnet poles may include between three and eight hill sectors alternating with a same number of valley sectors distributed about a central axis. The lip of the abyssal opening may be positioned at a distance from the corresponding valley peripheral edge. The flux return yoke may have a thickness in the portions facing valley sectors, such that the ratio of the product of the distance times the thickness to the square of the distance of the peripheral edge to the central axis is less than 5%.