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Title: Method of automatic measurement and focus of an electron beam and apparatus therefor

An electron beam focusing system, including a plural slit-type Faraday beam trap, for measuring the diameter of an electron beam and automatically focusing the beam for welding. Beam size is determined from profiles of the current measured as the beam is swept over at least two narrow slits of the beam trap. An automated procedure changes the focus coil current until the focal point location is just below a workpiece surface. A parabolic equation is fitted to the calculated beam sizes from which optimal focus coil current and optimal beam diameter are determined.
 [1];  [2]
  1. (San Jose, CA)
  2. (Livermore, CA)
Issue Date:
OSTI Identifier:
Sandia Corporation (Albuquerque, NM) SNL
Patent Number(s):
US 5483036
Contract Number:
Research Org:
Sandia National Laboratories (SNL), Albuquerque, NM, and Livermore, CA
Country of Publication:
United States
method; automatic; measurement; focus; electron; beam; apparatus; focusing; including; plural; slit-type; faraday; trap; measuring; diameter; automatically; welding; size; determined; profiles; current; measured; swept; narrow; slits; automated; procedure; changes; coil; focal; location; below; workpiece; surface; parabolic; equation; fitted; calculated; sizes; optimal; workpiece surface; electron beam; beam trap; narrow slit; beam focus; beam focusing; /219/250/324/