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Title: Charge amplifier with bias compensation

Abstract

An ion beam uniformity monitor for very low beam currents using a high-sensitivity charge amplifier with bias compensation. The ion beam monitor is used to assess the uniformity of a raster-scanned ion beam, such as used in an ion implanter, and utilizes four Faraday cups placed in the geometric corners of the target area. Current from each cup is integrated with respect to time, thus measuring accumulated dose, or charge, in Coulombs. By comparing the dose at each corner, a qualitative assessment of ion beam uniformity is made possible. With knowledge of the relative area of the Faraday cups, the ion flux and areal dose can also be obtained.

Inventors:
 [1]
  1. Livermore, CA
Issue Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
OSTI Identifier:
874671
Patent Number(s):
6437342
Assignee:
The Regents of the University of California (Oakland, CA)
Patent Classifications (CPCs):
H - ELECTRICITY H01 - BASIC ELECTRIC ELEMENTS H01J - ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
charge; amplifier; bias; compensation; beam; uniformity; monitor; currents; high-sensitivity; assess; raster-scanned; implanter; utilizes; faraday; cups; placed; geometric; corners; target; current; cup; integrated; time; measuring; accumulated; dose; coulombs; comparing; corner; qualitative; assessment; knowledge; flux; areal; obtained; beam current; charge amplifier; beam monitor; /250/

Citation Formats

Johnson, Gary W. Charge amplifier with bias compensation. United States: N. p., 2002. Web.
Johnson, Gary W. Charge amplifier with bias compensation. United States.
Johnson, Gary W. Tue . "Charge amplifier with bias compensation". United States. https://www.osti.gov/servlets/purl/874671.
@article{osti_874671,
title = {Charge amplifier with bias compensation},
author = {Johnson, Gary W},
abstractNote = {An ion beam uniformity monitor for very low beam currents using a high-sensitivity charge amplifier with bias compensation. The ion beam monitor is used to assess the uniformity of a raster-scanned ion beam, such as used in an ion implanter, and utilizes four Faraday cups placed in the geometric corners of the target area. Current from each cup is integrated with respect to time, thus measuring accumulated dose, or charge, in Coulombs. By comparing the dose at each corner, a qualitative assessment of ion beam uniformity is made possible. With knowledge of the relative area of the Faraday cups, the ion flux and areal dose can also be obtained.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2002},
month = {1}
}

Patent:

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