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:
-
- Livermore, CA
- Issue Date:
- Research Org.:
- Lawrence Livermore National Laboratory (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}
}
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