Patent ID: 6265959
Filing Date: 2001-07-24
Classification: G01R,H01F

Abstract:
A magnetic structure for generating a uniform magnetic field within a region of interest within a cavity, comprising:a) a plurality of uniformly-magnetized, prism-shaped blocks of permanent magnet material being positioned around a cavity within the magnetic structure leaving an opening allowing access to the cavity,b) said magnetic structure having a plane surface comprising a discrete high permeability ferromagnetic member interfacing with the cavity and acting as a single pole piece of the magnetic structure from which magnetic flux constituting the uniform magnetic field flows through the region of interest in the cavity toward the opening, said high-permeability ferromagnetic member being positioned underneath an object when placed within the region of interest to be analyzed in the presence of the uniform magnetic field, said opening being opposed to the high-permeability ferromagnetic member acting as the single pole piece and providing access to the region of interest and to the object when placed therein, said magnetic structure lacking a discrete high-permeability ferromagnetic member acting as a discrete second pole piece at the location of the opening, said magnetic structure portions adjacent the opening collecting the magnetic flux flowing through the single pole piece and through the region of interest in the cavity,c) said prism-shaped blocks of permanent magnet material being responsible for the generation of the uniform magnetic field within the region of interest,d) said magnetic structure being configured such that a magnetic equipotential surface is formed across the opening.