STFC in collaboration with CERN has developed a new type of adjustable permanent magnet based quadrupole for the CLIC Drive Beam Decelerator. It uses vertical movement of permanent magnets to achieve a desired integrated gradient range. The multipole magnet is capable of producing a high quality, adjustable magnetic field that does not require an external power supply or cooling system, and which can be constructed within a minimal volume.

IP TYPE

Patents

VIDEO

DESCRIPTION

The design uses a number of ferromagnetic poles and permanent magnets with an appropriate magnetisation direction and movable position in the plane of the pole. The permanent magnets supply a controlled magnetomotive force to the ferromagnetic poles along with a number of ferromagnetic flux conducting members to produce a desired magnetic field.

An even number of ferromagnetic poles are used such that there are pairs of diametrically opposing poles. Ferromagnetic bridges (conducting members) are used to channel magnetic flux between the permanent magnets of two adjacent poles. The permanent magnets may be moved away from the poles to reduce the field. Additionally, if the conducting members are moved closer to the permanent magnets in order to create a short circuit, the magnetic field strength in the beamline space is reduced. Relative movements between the permanent magnets and conducing members also create air gaps which reduce the magnetic field strength. A possible embodiment of the multipole magnet is to have four ferromagnetic poles and two permanent magnets.

INNOVATIONS

An arrangement of ferromagnetic poles, movable permanent magnets and conducting bridges system which offers great control over the field without any electric supply.

ADVANTAGES

• The multipole magnet is capable of producing a high quality, adjustable magnetic field that does not require an external power supply or cooling system, and which can be constructed within a minimal volume.
• No power supply is required and so large numbers of these multipole magnets can be operated at a considerably lower cost compared with a similar number of electromagnetic multipole magnets.

DOMAIN OF APPLICATION

Deflecting, focusing or otherwise altering the characteristics of a beam of charged particles. The multipole magnet is particularly suited to use in beamlines where space is particularly restricted (e.g. in a shielded enclosure, such as a tunnel) or where the reduction in heat dissipation into the surrounding space is a constraint.