Patent ID: 6515287
Filing Date: 2003-02-04
Classification: H01J

Abstract:
A magnetic lens configured to apply a magnetic field to a charged particle beam during use, comprising:an outer pole piece and an inner pole piece, wherein the outer pole piece is magnetically coupled to the inner pole piece, wherein the outer pole piece comprises at least two sectors and at least two slots, wherein each sector is disposed between lateral boundaries of the two slots of the outer pole piece, and wherein the charged particle beam is configured to pass through the magnetic lens from a first end of the magnetic lens to a second end of the magnetic lens during use; a primary coil winding interposed between the outer pole piece and the inner pole piece, wherein the primary coil winding is configured to drive a magnetic potential of the outer pole piece relative to the inner pole piece during use; and at least two sector coil windings, wherein each sector coil winding is coupled to one sector of the outer pole piece, wherein each sector coil winding is configured to drive a magnetic potential of one sector of the outer pole piece during use, and wherein the magnetic field applied to the charged particle beam comprises the magnetic potential of the outer pole piece and the magnetic potential,of at least one sector of the outer pole piece.