Patent ID: 6818906
Filing Date: 2004-11-16
Classification: H01J

Abstract:
An apparatus for relating the position of an electron beam traveling in a vacuum chamber along a beam axis to a mechanical reference, the apparatus comprising:an outer support member adapted for motion along a first transverse axis and flexibly mounted to a reference frame; an inner support member adapted for motion along a second transverse axis and flexibly mounted within said outer support member; and a beam-detecting unit in a reference plate supported by said inner support member, said reference plate comprising a central aperture permitting the passage of the electron beam, a scattering unit for scattering electrons from said electron beam, a detector for detecting electrons scattered from said electron beam by said scattering unit and a set of reference mirrors oriented along said first and second transverse axes, whereby signals from said detector representing the position of said beam relative to said detector may be associated with measurements of the position of said reference mirrors.