A cryogenic magnet structure includes at least two superconducting coils that are substantially symmetric about a central axis and on opposite sides of a median plane. At least one cryostat contains the superconducting coils; and a magnetic yoke surrounds the superconducting coils and contains at least a portion of a chamber, wherein the median plane extends through the chamber. At least one integral maintenance boot assembly is in thermal contact with the superconducting coils and is configured to preserve a sealed vacuum in the cryostat; and a cryogenic refrigerator is in thermal contact with the maintenance boot assembly and is configured to cool the superconducting coils below their critical superconducting temperatures and is configured for removal from thermal contact with the integral maintenance boot assembly without breaking the sealed vacuum in the cryostat.

The present invention provides a particle projection spatial imaging system, comprising a particle source for generating and accelerating a particle beam, a deflection coil set for deflecting the particle beam into a chronologically deployed dynamic 3D particle array, an exciting coil set for generating a magnetic field, and a scan control mechanism for controlling the particle source, the deflection coil set, and the particle exciting coil set. The particle projection spatial imaging system set forth by the present invention generates a 3D spatial image by generating and accelerating a particle beam by providing a particle source, deflecting the particle beam by using a deflection coil set to form a dynamic 3D particle array, and exciting particle bunches at corresponding pixel points in the array in a time-division manner by a particle exciting coil set to cause them to generate a radiation effect, and this particle projection spatial imaging system does not rely on a solid display medium, and can operate in the air and in vacuum. A 3D dynamic image can be generated by refreshing the scan control mechanism.

A magnet device that includes upper and lower disk-shaped return yokes, a pair of upper magnetic pole and lower magnetic pole respectively fixed to a disk-shaped surface of the upper return yoke and a disk-shaped surface of the lower return yoke, in which a space to circulate and accelerate an ion beam is formed between the upper magnetic pole and the lower magnetic pole. The upper magnetic pole and the lower magnetic pole have a plurality of concave and convex parts along a track along which the ion beam circulates, are plane-symmetrical with respect to a horizontal symmetry plane formed by the track along which an ion beam circulates, and are plane-symmetrical to one of the vertical planes vertical to the horizontal symmetry plane. Also, the magnetic pole intervals between the concave parts of the upper magnetic pole and the lower magnetic pole are different from each other.

A magnet device that includes upper and lower disk-shaped return yokes, a pair of upper magnetic pole and lower magnetic pole respectively fixed to a disk-shaped surface of the upper return yoke and a disk-shaped surface of the lower return yoke, in which a space to circulate and accelerate an ion beam is formed between the upper magnetic pole and the lower magnetic pole. The upper magnetic pole and the lower magnetic pole have a plurality of concave and convex parts along a track along which the ion beam circulates, are plane-symmetrical with respect to a horizontal symmetry plane formed by the track along which an ion beam circulates, and are plane-symmetrical to one of the vertical planes vertical to the horizontal symmetry plane. Also, the magnetic pole intervals between the concave parts of the upper magnetic pole and the lower magnetic pole are different from each other.

Conventional cyclotrons have been incapable of changing energy of a beam to be extracted. Conventional synchrotrons have been difficult to output beams in a continuous manner. An accelerator has a dense region dense region in which orbits of different energies densely gather as a result of using a radiofrequency electric field to accelerate an ion orbiting in an isochronous magnetic field in order to cause a beam orbit to be displaced in a specific direction with increasing acceleration, and a sparse region in which orbits of different energies are sparsely discrete from each other. The accelerator has a feature that a magnetic field has a magnetic field gradient in a radial direction of a beam orbit in the dense region, and a product of a gradient of magnetic field gradient and a beam size passing through the dense region becomes smaller than the magnetic field gradient.

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).

An electromagnetic field control member includes an insulating member constituted of a cylindrical ceramic and having a plurality of through holes along an axial direction, a conductive member constituted of metal and closing the through holes so as to provide an opening that opens in an outer periphery of the insulating member, and a power supply terminal connected to the conductive member. The power supply terminal is located away from an inner wall of the insulating member forming the through holes, and has a first end and a second end in the axial direction, and at least one of the first end and the second end is located farther away from the inner wall than a central portion of the power supply terminal.

An electromagnetic field control member includes an insulating member constituted of a cylindrical ceramic and having a plurality of through holes along an axial direction, a conductive member constituted of metal and closing the through holes so as to provide an opening that opens in an outer periphery of the insulating member, and a power supply terminal connected to the conductive member. The power supply terminal is located away from an inner wall of the insulating member forming the through holes, and has a first end and a second end in the axial direction, and at least one of the first end and the second end is located farther away from the inner wall than a central portion of the power supply terminal.

A particle therapy apparatus configured to scan a charged particle beam over a target according to a pre-defined treatment field which covers a treatment surface in an isocenter plane of the apparatus. The apparatus is capable of scanning the beam over a reachable surface which covers and is larger than the treatment surface. A beam stopper is arranged downstream of the scanning magnets of the apparatus, at a position to prevent the beam from reaching at least a portion of the reachable surface and to allow the beam to reach any portion of the treatment surface. A control system is configured to control the apparatus to direct the beam to the beam stopper and to meanwhile measure a position of the beam, to calculate a difference between a desired position and the measured position of the beam when directed to the beam stopper, and to scan the beam over the target according to the pre-defined treatment field by taking into account the calculated difference.

Charged particles are accelerated in a direct-current synchrotron, wherein a plurality of achromatic magnets define an acceleration device. A beam of charged particles is directed toward one of the magnets, and the charged-particle beam penetrates a gap in the magnet and is repeatedly redirected through an arc of at least 270 via inverse reflection at each of the achromatic magnets to produce a series of beam lines that form a circuit in which the charge-particle beam is accelerated over successive passes through the circuit. The achromatic magnets generate a constant magnetic field. The charged particles can then be extracted from the acceleration device.