Racetrack Dipoles or Quadropoles

These magnets are a variation of a Radial Access Port Magnet. The difference is that the windings have been elongated along the length of the radial port path. A dipole version has two elongated coils opposite each other. A quadropole or quadrupole magnet has four coils symmetrically spaced around the radial bore. Quadropoles produce a higher degree of field homogeneity and strength as compared to dipoles.

The achievable field in magnets of this type is lower than that of comparably sized solenoids wound with the same material since the field at the windings is considerably higher than that at the center of the magnets. Typically, a radial access port magnet having a central field of 7 Tesla will have a peak field on the windings of 8-8.5 Tesla. In addition, high homogeneities are more difficult to attain in these magnets than in solenoids.

A cylindrical metal former with machined pockets to accept each coil is normally used as a coil form. This former can have either a cold or vacuum bore which is perpendicular to the field direction.  Current lugs, protection circuit devices and persistent switches can be provided.

These magnets are quite versatile and can be used for a great variety of purposes, including:

Ioffe particle traps, beam lines, .