Patent ID: 6521888
Filing Date: 2003-02-18
Classification: H01J

Abstract:
An inverted orbit plasma mass filter with an inwardly directed radial electric field which comprises:a substantially cylindrical shaped container defining a longitudinal axis; a substantially cylindrical shaped collector oriented along said axis to establish a plasma chamber between said container and said collector; a magnetic means for generating a substantially uniform magnetic field (B), said magnetic field being substantially parallel to said axis in said chamber; an electric means for generating a radially oriented electric field (E) in said chamber, said electric field being directed inwardly from said container toward said collector; and a source for providing a multi-species plasma in said chamber, said multi-species plasma including charged particles (M1) of relatively low mass to charge ratio and charged particles (M2) of relatively high mass to charge ratio, wherein said multi-species plasma has a low collisional density in said chamber, and wherein said multi-species plasma is provided in a region of said chamber to allow substantially all of said high mass particles (M2) to move under an influence of said electric field (E) and said magnetic field (B) toward said axis and into contact with said collector, while preventing substantially all of said low mass particles (M1) from moving under an influence of said electric field (E) and said magnetic field (B) into contact with said collector.