Magnet apparatus for generating high gradient magnetic field

A method of generating at least one of a high gradient and high strength magnetic field, the method comprising providing a magnet apparatus, the magnet apparatus comprising:

• two permanent magnets located side-by-side with oppositely oriented magnetic field polarities and end surfaces of opposite polarities next to one another, the magnetic anisotropy of the magnets exceeding the magnetic induction of the material of the magnets;
• at least one mask on a first end of each of the adjacent permanent magnets, the at least one mask comprising a non-retentive material covering adjacent end surfaces of the two permanent magnets with a gap along a joining line between the two permanent magnets to form a zone of high-gradient magnetic field above the joining line;
• and
• at least one mask is at least one of embedded within the magnets and has a varying thickness.

A method for separation of particles comprising:

• using a magnet apparatus, the magnet apparatus comprising:
• two permanent magnets located side-by-side with oppositely oriented magnetic field polarities and end surfaces of opposite polarities next to one another, the magnetic anisotropy of the magnets exceeding the magnetic induction of the material of the magnets;
• at least one mask on a first end of each of the adjacent permanent magnets, the at least one mask comprising a non-retentive material covering adjacent end surfaces of the two permanent magnets with a gap along a joining line between the two permanent magnets to form a zone of high-gradient magnetic field above the joining line;
• and
• at least one mask is at least one of embedded within the magnets and has a varying thickness;
• and
• exposing the particles to be separated to the magnetic field generated by the magnet apparatus.