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Title: Negative ion source with external RF antenna

Abstract

A radio frequency (RF) driven plasma ion source has an external RF antenna, i.e. the RF antenna is positioned outside the plasma generating chamber rather than inside. The RF antenna is typically formed of a small diameter metal tube coated with an insulator. An external RF antenna assembly is used to mount the external RF antenna to the ion source. The RF antenna tubing is wound around the external RF antenna assembly to form a coil. The external RF antenna assembly is formed of a material, e.g. quartz, which is essentially transparent to the RF waves. The external RF antenna assembly is attached to and forms a part of the plasma source chamber so that the RF waves emitted by the RF antenna enter into the inside of the plasma chamber and ionize a gas contained therein. The plasma ion source is typically a multi-cusp ion source. A converter can be included in the ion source to produce negative ions.

Inventors:
; ;
Publication Date:
Research Org.:
The Regents of the University of California, Oakland, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1176106
Patent Number(s):
7,176,469
Application Number:
10/656,848
Assignee:
The Regents of the University of California (Oakland, CA) OSTI
DOE Contract Number:
AC03-76SF00098
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Citation Formats

Leung, Ka-Ngo, Hahto, Sami K., and Hahto, Sari T. Negative ion source with external RF antenna. United States: N. p., 2007. Web.
Leung, Ka-Ngo, Hahto, Sami K., & Hahto, Sari T. Negative ion source with external RF antenna. United States.
Leung, Ka-Ngo, Hahto, Sami K., and Hahto, Sari T. Tue . "Negative ion source with external RF antenna". United States. doi:. https://www.osti.gov/servlets/purl/1176106.
@article{osti_1176106,
title = {Negative ion source with external RF antenna},
author = {Leung, Ka-Ngo and Hahto, Sami K. and Hahto, Sari T.},
abstractNote = {A radio frequency (RF) driven plasma ion source has an external RF antenna, i.e. the RF antenna is positioned outside the plasma generating chamber rather than inside. The RF antenna is typically formed of a small diameter metal tube coated with an insulator. An external RF antenna assembly is used to mount the external RF antenna to the ion source. The RF antenna tubing is wound around the external RF antenna assembly to form a coil. The external RF antenna assembly is formed of a material, e.g. quartz, which is essentially transparent to the RF waves. The external RF antenna assembly is attached to and forms a part of the plasma source chamber so that the RF waves emitted by the RF antenna enter into the inside of the plasma chamber and ionize a gas contained therein. The plasma ion source is typically a multi-cusp ion source. A converter can be included in the ion source to produce negative ions.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Feb 13 00:00:00 EST 2007},
month = {Tue Feb 13 00:00:00 EST 2007}
}

Patent:

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  • A radio frequency (RF) driven plasma ion source has an external RF antenna, i.e. the RF antenna is positioned outside the plasma generating chamber rather than inside. The RF antenna is typically formed of a small diameter metal tube coated with an insulator. An external RF antenna assembly is used to mount the external RF antenna to the ion source. The RF antenna tubing is wound around the external RF antenna assembly to form a coil. The external RF antenna assembly is formed of a material, e.g. quartz, which is essentially transparent to the RF waves. The external RF antennamore » assembly is attached to and forms a part of the plasma source chamber so that the RF waves emitted by the RF antenna enter into the inside of the plasma chamber and ionize a gas contained therein. The plasma ion source is typically a multi-cusp ion source.« less
  • An antenna comprises a plurality of small diameter conductive wires disposed in a dielectric tube. The number and dimensions of the conductive wires is selected to improve the RF resistance of the antenna while also facilitating a reduction in thermal gradients that may create thermal stresses on the dielectric tube. The antenna may be mounted in a vacuum system using a low-stress antenna assembly that cushions and protects the dielectric tube from shock and mechanical vibration while also permitting convenient electrical and coolant connections to the antenna.
  • Electromagnetic modeling of the multicusp external antenna H ion source for the Spallation Neutron Source SNS has been performed in order to optimize high-power performance. During development of the SNS external antenna ion source, antenna failures due to high voltage and multicusp magnet holder rf heating concerns under stressful operating conditions led to rf characteristics analysis. In rf simulations, the plasma was modeled as an equivalent lossy metal by defining conductivity as . Insulation designs along with material selections such as ferrite and Teflon could be included in the computer simulations to compare antenna gap potentials, surface power dissipations, andmore » input impedance at the operating frequencies, 2 and 13.56 MHz. Further modeling and design improvements are outlined in the conclusion.« less
  • Electromagnetic modeling of the multicusp external antenna H{sup -} ion source for the Spallation Neutron Source (SNS) has been performed in order to optimize high-power performance. During development of the SNS external antenna ion source, antenna failures due to high voltage and multicusp magnet holder rf heating concerns under stressful operating conditions led to rf characteristics analysis. In rf simulations, the plasma was modeled as an equivalent lossy metal by defining conductivity as {sigma}. Insulation designs along with material selections such as ferrite and Teflon could be included in the computer simulations to compare antenna gap potentials, surface power dissipations,more » and input impedance at the operating frequencies, 2 and 13.56 MHz. Further modeling and design improvements are outlined in the conclusion.« less
  • No abstract prepared.