초록 ▼

A cyclotron having a cylindrical superconducting magnet which generates an axial magnetic field and has a central opening or chamber of substantially circular cross-section. The accelerating beam space is located in this chamber lying normal to the axis of the magnetic field. The azimuth variation o

A cyclotron having a cylindrical superconducting magnet which generates an axial magnetic field and has a central opening or chamber of substantially circular cross-section. The accelerating beam space is located in this chamber lying normal to the axis of the magnetic field. The azimuth variation of magnetic field as well as the isochronous radial variation of magnetic field required to control the orbiting of the ion beam in the beam space, are provided by ferro-magnetic pole pieces located in the axial chamber, which interact with the magnetic field to cause the required field variations. Interposed between the pole pieces are resonant frequency members which provide the radio frequency energization to accelerate the ion beam around the beam space. Having the whole of the central chamber free for top and bottom access enables the pole pieces to be given an efficient design shape. Also, the radio frequency members are able to be interposed between the pole pieces and are not restricted as to axial length and so can be made a very efficient length, such as quarter wave length resonators. The radio frequency members have axially extending hollow interiors which open into the beam space and this enables vacuum pumping to communicate through these interiors thus allowing very efficient pumping of the beam space. There is no iron yoke for the magnet and the weight and size are consequently much reduced and the cyclotron is highly transportable.

대표청구항 ▼

A cyclotron comprising a superconducting magnet having at least one cylindrical magnet coil arranged in a cryostat to provide a magnetic field extending axially of said coil, said cryostat defining an axial chamber having a substantially circular cross-section and containing said magnetic field, whe

A cyclotron comprising a superconducting magnet having at least one cylindrical magnet coil arranged in a cryostat to provide a magnetic field extending axially of said coil, said cryostat defining an axial chamber having a substantially circular cross-section and containing said magnetic field, wherein said superconducting magnet provides yokeless means for generating said magnetic field, wherein interacting means are disposed in said chamber and arranged to interact with said magnetic field to provide a ‘flutter’or variation of the axial magnetic field in the azimuthal direction in relation to said axis and to provide an isochronous variation of said axial magnetic field in the radial direction from said axis, wherein resonant cavity means are disposed in said chamber and arranged to provide an accelerating field for a beam of ionized particles, said interacting means and said resonant cavity means together defining a beam space disposed in the radial direction from said axis in which said beam of ionized particles is accelerated, and wherein each said at least one cylindrical magnet coil defines an internal radius greater than the radius defined by said beam space.