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Title: Studies in High Current Density Ion Sources for Heavy Ion Fusion Applications

Abstract

This dissertation develops diverse research on small (diameter ~ few mm), high current density (J ~ several tens of mA/cm 2) heavy ion sources. The research has been developed in the context of a programmatic interest within the Heavy Ion Fusion (HIF) Program to explore alternative architectures in the beam injection systems that use the merging of small, bright beams. An ion gun was designed and built for these experiments. Results of average current density yield (<J>) at different operating conditions are presented for K + and Cs + contact ionization sources and potassium aluminum silicate sources. Maximum <J> values for a K + beam of ~90 mA/cm 2 were observed in 2.3 μs pulses. Measurements of beam intensity profiles and emittances are included. Measurements of neutral particle desorption are presented at different operating conditions which lead to a better understanding of the underlying atomic diffusion processes that determine the lifetime of the emitter. Estimates of diffusion times consistent with measurements are presented, as well as estimates of maximum repetition rates achievable. Diverse studies performed on the composition and preparation of alkali aluminosilicate ion sources are also presented. In addition, this work includes preliminary work carried out exploring the viabilitymore » of an argon plasma ion source and a bismuth metal vapor vacuum arc (MEVVA) ion source. For the former ion source, fast rise-times (~ 1 μs), high current densities (~ 100 mA/cm +) and low operating pressures (< 2 mtorr) were verified. For the latter, high but acceptable levels of beam emittance were measured (ε n ≤ 0.006 π· mm · mrad) although measured currents differed from the desired ones (I ~ 5mA) by about a factor of 10.« less

Authors:
 [1]
  1. Univ. of California, Berkeley, CA (United States)
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
920171
Report Number(s):
LBNL-62694
TRN: US0805664
DOE Contract Number:  
AC02-05CH11231
Resource Type:
Thesis/Dissertation
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ALUMINIUM; ARGON; BEAM EMITTANCE; BEAM INJECTION; BISMUTH; CURRENT DENSITY; DESORPTION; DIFFUSION; HEAVY IONS; ION SOURCES; IONIZATION; LIFETIME; NEUTRAL PARTICLES; POTASSIUM; SILICATES; VIABILITY

Citation Formats

Chacon-Golcher, Edwin. Studies in High Current Density Ion Sources for Heavy Ion Fusion Applications. United States: N. p., 2002. Web. doi:10.2172/920171.
Chacon-Golcher, Edwin. Studies in High Current Density Ion Sources for Heavy Ion Fusion Applications. United States. doi:10.2172/920171.
Chacon-Golcher, Edwin. Sat . "Studies in High Current Density Ion Sources for Heavy Ion Fusion Applications". United States. doi:10.2172/920171. https://www.osti.gov/servlets/purl/920171.
@article{osti_920171,
title = {Studies in High Current Density Ion Sources for Heavy Ion Fusion Applications},
author = {Chacon-Golcher, Edwin},
abstractNote = {This dissertation develops diverse research on small (diameter ~ few mm), high current density (J ~ several tens of mA/cm2) heavy ion sources. The research has been developed in the context of a programmatic interest within the Heavy Ion Fusion (HIF) Program to explore alternative architectures in the beam injection systems that use the merging of small, bright beams. An ion gun was designed and built for these experiments. Results of average current density yield (<J>) at different operating conditions are presented for K+ and Cs+ contact ionization sources and potassium aluminum silicate sources. Maximum <J> values for a K+ beam of ~90 mA/cm2 were observed in 2.3 μs pulses. Measurements of beam intensity profiles and emittances are included. Measurements of neutral particle desorption are presented at different operating conditions which lead to a better understanding of the underlying atomic diffusion processes that determine the lifetime of the emitter. Estimates of diffusion times consistent with measurements are presented, as well as estimates of maximum repetition rates achievable. Diverse studies performed on the composition and preparation of alkali aluminosilicate ion sources are also presented. In addition, this work includes preliminary work carried out exploring the viability of an argon plasma ion source and a bismuth metal vapor vacuum arc (MEVVA) ion source. For the former ion source, fast rise-times (~ 1 μs), high current densities (~ 100 mA/cm+) and low operating pressures (< 2 mtorr) were verified. For the latter, high but acceptable levels of beam emittance were measured (εn ≤ 0.006 π· mm · mrad) although measured currents differed from the desired ones (I ~ 5mA) by about a factor of 10.},
doi = {10.2172/920171},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sat Jun 01 00:00:00 EDT 2002},
month = {Sat Jun 01 00:00:00 EDT 2002}
}

Thesis/Dissertation:
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