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Title: Experiments with planar inductive ion source meant for creation ofH+ Beams

Abstract

In this article the effect of different engineering parameters of an rf-driven ion sources with external spiral antenna and quartz disk rf-window are studied. Paper consists of three main topics: The effect of source geometry on the operation gas pressure, the effect of source materials and magnetic confinement on extracted current density and ion species and the effect of different antenna geometries on the extracted current density. The operation gas pressure as a function of the plasma chamber diameter, was studied. This was done with three cylindrical plasma chambers with different inner diameters. The chamber materials were studied using two materials, aluminum and alumina (AlO{sub 2}). The removable 14 magnet multicusp confinement arrangement enabled us to compare the effects of the two wall materials with and without the magnetic confinement. Highest proton fraction of {approx} 8% at 2000 W of rf-power and at pressure of 1.3 Pa was measured using AlO{sub 2} plasma chamber and no multicusp confinement. For all the compared ion sources at 1000W of rf-power, source with multicusp confinement and AlO2 plasma chamber yields highest current density of 82.7 mA/cm{sup 2} at operation pressure of 4 Pa. From the same source highest measured current density of 143more » mA/cm{sup 2} at 1.3 Pa and 2200W of rf-power was achieved. Multicusp confinement increased the maximum extracted current up to factor of two. Plasma production with different antenna geometries was also studied. Antenna tests were performed using same source geometry as in source material study with AlO{sub 2} plasma chamber and multicusp confinement. The highest current density was achieved with 4.5 loop solenoid antenna with 6 cm diameter. Slightly lower current density with lower pressure was achieved using tightly wound 3 loop spiral antenna with 3.3 cm ID and 6 cm OD.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
Sponsoring Org.:
USDOE
OSTI Identifier:
928770
Report Number(s):
LBNL-61784
Journal ID: ISSN 0034-6748; RSINAK; R&D Project: Z2IS10 Z2IS14; TRN: US0803256
DOE Contract Number:
DE-AC02-05CH11231
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 78; Journal Issue: 6; Related Information: Journal Publication Date: 06/2007
Country of Publication:
United States
Language:
English
Subject:
70; ALUMINIUM; ANTENNAS; CONFINEMENT; CURRENT DENSITY; GEOMETRY; ION SOURCES; MAGNETIC CONFINEMENT; MAGNETS; PLASMA PRODUCTION; PROTONS; QUARTZ; SOLENOIDS; Ion Source External RF-antenna Planar inductive source Plasmasource

Citation Formats

Vainionpaa, J.H., Kalvas, T., Hahto, S.K., and Reijonen, J.. Experiments with planar inductive ion source meant for creation ofH+ Beams. United States: N. p., 2007. Web. doi:10.1063/1.2742624.
Vainionpaa, J.H., Kalvas, T., Hahto, S.K., & Reijonen, J.. Experiments with planar inductive ion source meant for creation ofH+ Beams. United States. doi:10.1063/1.2742624.
Vainionpaa, J.H., Kalvas, T., Hahto, S.K., and Reijonen, J.. Wed . "Experiments with planar inductive ion source meant for creation ofH+ Beams". United States. doi:10.1063/1.2742624. https://www.osti.gov/servlets/purl/928770.
@article{osti_928770,
title = {Experiments with planar inductive ion source meant for creation ofH+ Beams},
author = {Vainionpaa, J.H. and Kalvas, T. and Hahto, S.K. and Reijonen, J.},
abstractNote = {In this article the effect of different engineering parameters of an rf-driven ion sources with external spiral antenna and quartz disk rf-window are studied. Paper consists of three main topics: The effect of source geometry on the operation gas pressure, the effect of source materials and magnetic confinement on extracted current density and ion species and the effect of different antenna geometries on the extracted current density. The operation gas pressure as a function of the plasma chamber diameter, was studied. This was done with three cylindrical plasma chambers with different inner diameters. The chamber materials were studied using two materials, aluminum and alumina (AlO{sub 2}). The removable 14 magnet multicusp confinement arrangement enabled us to compare the effects of the two wall materials with and without the magnetic confinement. Highest proton fraction of {approx} 8% at 2000 W of rf-power and at pressure of 1.3 Pa was measured using AlO{sub 2} plasma chamber and no multicusp confinement. For all the compared ion sources at 1000W of rf-power, source with multicusp confinement and AlO2 plasma chamber yields highest current density of 82.7 mA/cm{sup 2} at operation pressure of 4 Pa. From the same source highest measured current density of 143 mA/cm{sup 2} at 1.3 Pa and 2200W of rf-power was achieved. Multicusp confinement increased the maximum extracted current up to factor of two. Plasma production with different antenna geometries was also studied. Antenna tests were performed using same source geometry as in source material study with AlO{sub 2} plasma chamber and multicusp confinement. The highest current density was achieved with 4.5 loop solenoid antenna with 6 cm diameter. Slightly lower current density with lower pressure was achieved using tightly wound 3 loop spiral antenna with 3.3 cm ID and 6 cm OD.},
doi = {10.1063/1.2742624},
journal = {Review of Scientific Instruments},
number = 6,
volume = 78,
place = {United States},
year = {Wed Feb 07 00:00:00 EST 2007},
month = {Wed Feb 07 00:00:00 EST 2007}
}
  • In this article the effects of different engineering parameters of rf-driven ion sources with an external spiral antenna and a quartz rf window are studied. This article consists of three main topics: the effect of source geometry on the operation gas pressure, the effect of source materials and magnetic confinement on extracted current density and ion species, and the effect of different antenna geometries on the extracted current density. The effect of source geometry was studied using three cylindrical plasma chambers with different inner diameters. The chamber materials were studied using two materials, aluminum (Al) and alumina (Al{sub 2}O{sub 3}).more » The removable 14 magnet multicusp confinement arrangement enabled us to compare the effects of the two wall materials with and without the magnetic confinement. The highest measured proton fractions were measured using Al{sub 2}O{sub 3} plasma chamber and no multicusp confinement. For the compared ion sources the source with multicusp confinement and Al{sub 2}O{sub 3} plasma chamber yields the highest current densities. Multicusp confinement increased the maximum extracted current by up to a factor of 2. Plasma production with different antenna geometries were also studied. The highest current density was achieved using 4.5 loop solenoid antenna with 6.0 cm diameter. A slightly lower current density with lower pressure was achieved using a tightly wound 3 loop spiral antenna with 3.3 cm inner diameter and 6 cm outer diameter.« less
  • At the Lawrence Berkeley National Laboratory a diagnostic neutral beam injection system for measuring plasma parameters, flow velocity, and local magnetic field is being developed. The system is designed to have a 90% proton fraction and small divergence with beam current at 5-6 A and a pulse length of {approx}1 s occurring once every 1-2 min. The ion source needs to generate uniform plasma over a large (8x5 cm{sup 2}) extraction area. For this application, we have compared rf driven multicusp ion sources operating with either an external or an internal antenna in similar ion source geometry. The ion beammore » will be made of an array of six sheet-shaped beamlets. The design is optimized using computer simulation programs.« less
  • A resonant planar antenna as an inductive plasma source operating at 13.56 MHz inside a low pressure vacuum vessel is presented for potential plasma processing applications. Its principle consists in interconnecting elementary resonant meshes composed of inductive and capacitive elements. Due to its structure, the antenna shows a set of resonant modes associated with peaks of the real input impedance. Each of these modes is defined by its own current and voltage distribution oscillating at the frequency of the mode. A rectangular antenna of 0.55mx0.20m has been built, and first results obtained with argon plasmas are presented. Plasma generation ismore » shown to be efficient as densities up to 4{center_dot}10{sup 17}m{sup -3} at 2000 W have been measured by microwave interferometry at a distance of 4 cm from the source plane. It is also demonstrated that the plasma couples inductively with the resonating currents flowing in the antenna above a threshold power of about 60 W. A non-uniformity of less than {+-}5% is obtained at 1000 W at a few centimeters above the antenna over 75% of its surface.« less
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