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Title: Low energy spread ion source with a coaxial magnetic filter

Abstract

Multicusp ion sources are capable of producing ions with low axial energy spread which are necessary in applications such as ion projection lithography (IPL) and radioactive ion beam production. The addition of a radially extending magnetic filter consisting of a pair of permanent magnets to the multicusp source reduces the energy spread considerably due to the improvement in the uniformity of the axial plasma potential distribution in the discharge region. A coaxial multicusp ion source designed to further reduce the energy spread utilizes a cylindrical magnetic filter to achieve a more uniform axial plasma potential distribution. The coaxial magnetic filter divides the source chamber into an outer annular discharge region in which the plasma is produced and a coaxial inner ion extraction region into which the ions radially diffuse but from which ionizing electrons are excluded. The energy spread in the coaxial source has been measured to be 0.6 eV. Unlike other ion sources, the coaxial source has the capability of adjusting the radial plasma potential distribution and therefore the transverse ion temperature (or beam emittance).

Inventors:
 [1];  [2]
  1. (Hercules, CA)
  2. (Berkeley, CA)
Issue Date:
Research Org.:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA
OSTI Identifier:
873116
Patent Number(s):
6094012
Assignee:
Regents of University of California (Oakland, CA) LBNL
DOE Contract Number:  
AC03-76SF00098
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
energy; spread; source; coaxial; magnetic; filter; multicusp; sources; capable; producing; axial; applications; projection; lithography; ipl; radioactive; beam; production; addition; radially; extending; consisting; pair; permanent; magnets; reduces; considerably; due; improvement; uniformity; plasma; potential; distribution; discharge; region; designed; reduce; utilizes; cylindrical; achieve; uniform; divides; chamber; outer; annular; produced; inner; extraction; diffuse; ionizing; electrons; excluded; measured; unlike; capability; adjusting; radial; transverse; temperature; emittance; outer annular; potential distribution; axial magnetic; projection lithography; magnetic filter; discharge region; permanent magnet; permanent magnets; radially extending; beam emittance; energy spread; source reduces; source designed; extraction region; source design; axial plasma; ionizing electrons; /315/250/

Citation Formats

Leung, Ka-Ngo, and Lee, Yung-Hee Yvette. Low energy spread ion source with a coaxial magnetic filter. United States: N. p., 2000. Web.
Leung, Ka-Ngo, & Lee, Yung-Hee Yvette. Low energy spread ion source with a coaxial magnetic filter. United States.
Leung, Ka-Ngo, and Lee, Yung-Hee Yvette. Sat . "Low energy spread ion source with a coaxial magnetic filter". United States. https://www.osti.gov/servlets/purl/873116.
@article{osti_873116,
title = {Low energy spread ion source with a coaxial magnetic filter},
author = {Leung, Ka-Ngo and Lee, Yung-Hee Yvette},
abstractNote = {Multicusp ion sources are capable of producing ions with low axial energy spread which are necessary in applications such as ion projection lithography (IPL) and radioactive ion beam production. The addition of a radially extending magnetic filter consisting of a pair of permanent magnets to the multicusp source reduces the energy spread considerably due to the improvement in the uniformity of the axial plasma potential distribution in the discharge region. A coaxial multicusp ion source designed to further reduce the energy spread utilizes a cylindrical magnetic filter to achieve a more uniform axial plasma potential distribution. The coaxial magnetic filter divides the source chamber into an outer annular discharge region in which the plasma is produced and a coaxial inner ion extraction region into which the ions radially diffuse but from which ionizing electrons are excluded. The energy spread in the coaxial source has been measured to be 0.6 eV. Unlike other ion sources, the coaxial source has the capability of adjusting the radial plasma potential distribution and therefore the transverse ion temperature (or beam emittance).},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2000},
month = {1}
}

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