CPC H01J 37/145 (2013.01) [H01J 2237/21 (2013.01)] | 10 Claims |
1. An anti-rotation lens having a focusing power for focusing a charged particle beam, comprising:
a magnetic lens configured to generate a magnetic field being aligned with an optical axis of the anti-rotation lens; and
an electrostatic lens configured to generate an electrostatic field being aligned with the optical axis, wherein the magnetic field and the electrostatic field at least partially overlap, and the focusing power of the anti-rotation lens is adjustable by varying the magnetic field and/or the electrostatic field.
|