COOLING MODULE FOR CHARGED PARTICLE BEAM COLUMN ELEMENTS

We have developed a method and apparatus for cooling electromagnetic lens coils of the kind used in charged particle beams. The method and apparatus provide not only a symmetrical cooling effect around the optical axis of the charged particle beam, but also provide improved uniformity of heat transfer. This improved uniformity enables control over the optical axis of the charged particle beam within about 1 nm for high current charged particle beam columns, wherein the current ranges from about 100 nanoamps to about 1000 nanoamps. The use of a squat and wide electromagnetic lens coil in combination with an essentially flat modular cooling panel, which provides uniform cooling to the electromagnetic lens coil, not only enables control over the optical axis of the charged particle beam, but also provides mechanical stability for the charged particle beam column.