Enhanced modified faraday cup for determination of power density distribution of electron beams

Patent · Mon Jan 01 00:00:00 EST 2001

OSTI ID:874046

Elmer, John W ^[1]; Teruya, Alan T ^[2]

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1. Danville, CA
2. Livermore, CA

An improved tomographic technique for determining the power distribution of an electron or ion beam using electron beam profile data acquired by an enhanced modified Faraday cup to create an image of the current density in high and low power ion or electron beams. A refractory metal disk with a number of radially extending slits, one slit being about twice the width of the other slits, is placed above a Faraday cup. The electron or ion beam is swept in a circular pattern so that its path crosses each slit in a perpendicular manner, thus acquiring all the data needed for a reconstruction in one circular sweep. The enlarged slit enables orientation of the beam profile with respect to the coordinates of the welding chamber. A second disk having slits therein is positioned below the first slit disk and inside of the Faraday cup and provides a shield to eliminate the majority of secondary electrons and ions from leaving the Faraday cup. Also, a ring is located below the second slit disk to help minimize the amount of secondary electrons and ions from being produced. In addition, a beam trap is located in the Faraday cup to provide even more containment of the electron or ion beam when full beam current is being examined through the center hole of the modified Faraday cup.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
• DOE Contract Number: W-7405-ENG-48
• Assignee: Regents of University of California (Oakland, CA)
• Patent Number(s): US 6300755
• OSTI ID: 874046
• Country of Publication: United States
• Language: English

Related Subjects

enhanced
modified
faraday
cup
determination
power
density
distribution
electron
beams
improved
tomographic
technique
determining
beam
profile
data
acquired
create
image
current
refractory
metal
disk
radially
extending
slits
slit
twice
width
placed
swept
circular
pattern
path
crosses
perpendicular
manner
acquiring
reconstruction
sweep
enlarged
enables
orientation
respect
coordinates
welding
chamber
therein
positioned
below
inside
provides
shield
eliminate
majority
secondary
electrons
leaving
located
help
minimize
amount
produced
addition
trap
provide
containment
examined
center
positioned below
located below
profile data
data acquired
tomographic technique
beam current
current density
refractory metal
electron beam
electron beams
radially extending
faraday cup
power density
density distribution
secondary electrons
power distribution
beam profile
modified faraday
secondary electron
beam trap
perpendicular manner
circular pattern
metal disk
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