METHOD AND STRUCTURE FOR CONTROLLING MAGNETIC FIELD DISTRIBUTION OF E×B WIEN FILTER

PROBLEM TO BE SOLVED: To provide a method and structure of adjusting the magnetic field distribution at the incident side and exit side end caps of a mass filter in an E×B mass filter.SOLUTION: Magnetic resistance of a magnetic flux in a return path can be changed by providing a plurality of magnetic shims in a slot provided in the outer diameter of the incident side and exit side end caps, and further providing a plurality of magnetic plug shims in a circular magnetic flux dam surrounding the incident side and exit side apertures. When compared with the conventional adjustment method of an electromagnet, the advantages of adjusting the magnetic field fully mechanically include high reliability, simplification, low cost and saving of power consumption. In order to generate a magnetic field of mass separation, any one of a permanent magnet or an electromagnet can be used.