Abstract: Forming poles from sectors of a tube of carbon or a material with similar conductive properties and supporting the poles by bonding an insulating support ring thereto before removing end rings formed at the ends of the tube which temporarily support the poles provides a multipole deflector element of robust structure of high dimensional accuracy and stability in which eddy current and charging effects are avoided. The manufacturing method is much simplified, reduced in cost and increased in reliability, repeatability and yield over manufacturing techniques for known multipole deflectors.

Abstract: A ferrite pole piece is mounted in an electromagnetic lens by placing a mounting ring around the pole piece and securing it with an adhesive. The internal diameter of the mounting ring is sufficiently greater than the outer diameter of the pole piece that the ferrite is not chipped when the mounting ring is placed around the pole piece. The pole piece, with the mounting ring secured, is inserted in a centering plate in the lens, and the mounting ring is secured to the centering plate.

Abstract: A magnetic lens having a lens bore for the passage of a particle beam includes a dynamic focus coil that is positioned outside the lens bore and within the pole piece that shapes the lens field, so that the magnetic flux lines from the dynamic focus coil all end on the pole pieces of the lens and the shape of the lens field between the pole pieces has its magnitude changed by the current passing through the dynamic focus coil, but the field shape is not changed, thus changing the focal plane of the beam without moving the beam transversely with respect to the system axis.

Abstract: A free-wound electromagnetic yoke is formed by winding the X-axis with a continuous piece of heat bondable wire wound around a plurality of coil forms positioned on a mandrel and turned by a lathe. After winding, the mandrel is heated to cause the windings to form solid coils. After cooling, the solid coils are removed from the mandrel and from the coil forms. The same process is repeated for the Y-axis. The solid coils for both the X-axis and the Y-axis are placed in a toroidal support ring to form an electromagnetic yoke.