Patent ID: 8358190

Claim:
A permanent magnet structure capable of generating a uniform magnetic field that is longitudinally directed, said magnet structure having a top and a bottom magnet subassembly, each subassembly comprised of: a. a base magnet having a rectangular cross-section, an inner flat longitudinal surface parallel to an outer flat longitudinal surface, a flat south pole at one end and a flat north pole at the opposite end and a magnetic polarity in the longitudinal direction; b. one or more first cladding magnets attached to and covering said outer flat longitudinal surface of said base magnet, having flat ends corresponding to the ends of said base magnet and having a polarity in the same direction as said base magnet; c. second cladding magnets attached to and only covering each end of said base magnet and the ends of said first cladding magnets and having a polarity in the general direction of said base magnet polarity; and d. said top and bottom subassemblies arranged such that their inner flat longitudinal surfaces are parallel to each other with their base magnet polarities in the same direction and separated by a space, whereby said space between said subassemblies constitutes a working region containing a longitudinal magnetic field with a magnetic polarity opposite to that of said base magnet polarities.