skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Neutral Beam Injection for Plasma and Magnetic FieldDiagnostics

Abstract

At the Lawrence Berkeley National Laboratory (LBNL) adiagnostic neutral beam injection system for measuring plasma parameters,flow velocity, and local magnetic field is being developed. High protonfraction and small divergence is essential for diagnostic neutral beams.In our design, a neutral hydrogen beam with an 8 cm x 11 cm (or smaller)elliptical beam spot at 2.5 m from the end of the extraction column isproduced. The beam will deliver up to 5 A of hydrogen beam to the targetwith a pulse width of ~;1 s, once every 1 - 2 min. The H1+ ion species ofthe hydrogen beamwill be over 90 percent. For this application, we havecompared two types of RF driven multicusp ion sources operating at 13.56MHz. The first one is an ion source with an external spiral antennabehind a dielectric RF-window. The second one uses an internal antenna insimilar ion source geometry. The source needs to generate uniform plasmaover a large (8 cm x 5 cm) extraction area. We expect that the ion sourcewith internal antenna will be more efficient at producing the desiredplasma density but might have the issue of limited antenna lifetime,depending on the duty factor. For both approaches there is a need forextra shielding to protect themore » dielectric materials from the backstreaming electrons. The source walls will be made of insulator materialsuch as quartz that has been observed to generate plasma with higheratomic fraction than sources with metal walls. The ion beam will beextracted and accelerated by a set of grids with slits, thus forming anarray of 6 sheet-shaped beamlets. The multiple grid extraction will beoptimized using computer simulation programs. Neutralization of the beamwill be done in neutralization chamber, which has over 70 percentneutralization efficiency.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
Sponsoring Org.:
USDOE
OSTI Identifier:
925529
Report Number(s):
LBNL-62477
R&D Project: Z2IS29; BnR: 600301010; TRN: US0803052
DOE Contract Number:  
DE-AC02-05CH11231
Resource Type:
Conference
Resource Relation:
Conference: 12 International Conference on Ion Sources, ICIS,Jeju, Korea, August 26-31, 2007
Country of Publication:
United States
Language:
English
Subject:
43; 70; ANTENNAS; BEAM INJECTION; COMPUTERIZED SIMULATION; DIELECTRIC MATERIALS; EFFICIENCY; ELECTRONS; EXTRACTION COLUMNS; GEOMETRY; HYDROGEN; ION BEAMS; ION SOURCES; LIFETIME; MAGNETIC FIELDS; PLASMA DENSITY; PROTONS; QUARTZ; SHIELDING; TARGETS; VELOCITY; Neutral Beams Plasma magnetic field diagnostics RF drivenmulticusp ion source

Citation Formats

Vainionpaa, Jaakko Hannes, Leung, Ka Ngo, Kwan, Joe W., and Levinton,Fred. Neutral Beam Injection for Plasma and Magnetic FieldDiagnostics. United States: N. p., 2007. Web.
Vainionpaa, Jaakko Hannes, Leung, Ka Ngo, Kwan, Joe W., & Levinton,Fred. Neutral Beam Injection for Plasma and Magnetic FieldDiagnostics. United States.
Vainionpaa, Jaakko Hannes, Leung, Ka Ngo, Kwan, Joe W., and Levinton,Fred. Wed . "Neutral Beam Injection for Plasma and Magnetic FieldDiagnostics". United States. doi:. https://www.osti.gov/servlets/purl/925529.
@article{osti_925529,
title = {Neutral Beam Injection for Plasma and Magnetic FieldDiagnostics},
author = {Vainionpaa, Jaakko Hannes and Leung, Ka Ngo and Kwan, Joe W. and Levinton,Fred},
abstractNote = {At the Lawrence Berkeley National Laboratory (LBNL) adiagnostic neutral beam injection system for measuring plasma parameters,flow velocity, and local magnetic field is being developed. High protonfraction and small divergence is essential for diagnostic neutral beams.In our design, a neutral hydrogen beam with an 8 cm x 11 cm (or smaller)elliptical beam spot at 2.5 m from the end of the extraction column isproduced. The beam will deliver up to 5 A of hydrogen beam to the targetwith a pulse width of ~;1 s, once every 1 - 2 min. The H1+ ion species ofthe hydrogen beamwill be over 90 percent. For this application, we havecompared two types of RF driven multicusp ion sources operating at 13.56MHz. The first one is an ion source with an external spiral antennabehind a dielectric RF-window. The second one uses an internal antenna insimilar ion source geometry. The source needs to generate uniform plasmaover a large (8 cm x 5 cm) extraction area. We expect that the ion sourcewith internal antenna will be more efficient at producing the desiredplasma density but might have the issue of limited antenna lifetime,depending on the duty factor. For both approaches there is a need forextra shielding to protect the dielectric materials from the backstreaming electrons. The source walls will be made of insulator materialsuch as quartz that has been observed to generate plasma with higheratomic fraction than sources with metal walls. The ion beam will beextracted and accelerated by a set of grids with slits, thus forming anarray of 6 sheet-shaped beamlets. The multiple grid extraction will beoptimized using computer simulation programs. Neutralization of the beamwill be done in neutralization chamber, which has over 70 percentneutralization efficiency.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Aug 01 00:00:00 EDT 2007},
month = {Wed Aug 01 00:00:00 EDT 2007}
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share: