Three-unit magnetic quadrupole lens system and manufacturing method thereof

The invention discloses a three-unit magnetic quadrupole lens system and a manufacturing method thereof. The three-unit magnetic quadrupole lens system comprises a three-unit magnetic quadrupole lens group formed by three lens units and a beam current transport pipeline passing through the center of the lens group. The beam current transport pipeline adopts an end sealing structure, and comprises a lens pipeline main body, a retainer ring flange, a retainer ring, an O-type sealing ring and an active flange. A dual-curve cylindrical surface-shaped magnetic pole surface is adopted, a magnetic equipotential surface of the quadrupole magnetic field is closer to the shape of dual curve, an ion beam can be easily debugged, and good focusing effects can be obtained. As a dual-curve cylindrical surface-shaped magnetic pole surface processing equation and magnetic pole surface breaking point coordinates are given, a numerical control machine tool can be used for extremely easily processing the dual-curve cylindrical surface-shaped magnetic pole surface precisely. The three-unit lens group enables debugging of the beam current to be more symmetrically. Vacuum sealing between the lens pipeline main body and the active flange is the end sealing, and the transport pipe has better vacuum sealing effects.