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Title: ECRIS operation with multiple frequencies.


No abstract prepared.

; ;
Publication Date:
Research Org.:
Argonne National Laboratory (ANL), Argonne,IL
Sponsoring Org.:
OSTI Identifier:
Report Number(s):
Journal ID: 0034-6748; TRN: US0700595
DOE Contract Number:
Resource Type:
Resource Relation:
Journal Name: Rev. Sci. Instrum.; Journal Volume: 77; Journal Issue: 3; Conference: International Conference on Ion Sources Caen, FranceSep 12-17, 2005
Country of Publication:
United States

Citation Formats

Vondrasek, R. C., Scott, R., and Pardo, R. C.. ECRIS operation with multiple frequencies.. United States: N. p., 2006. Web. doi:10.1063/1.2164895.
Vondrasek, R. C., Scott, R., & Pardo, R. C.. ECRIS operation with multiple frequencies.. United States. doi:10.1063/1.2164895.
Vondrasek, R. C., Scott, R., and Pardo, R. C.. Wed . "ECRIS operation with multiple frequencies.". United States. doi:10.1063/1.2164895.
title = {ECRIS operation with multiple frequencies.},
author = {Vondrasek, R. C. and Scott, R. and Pardo, R. C.},
abstractNote = {No abstract prepared.},
doi = {10.1063/1.2164895},
journal = {Rev. Sci. Instrum.},
number = 3,
volume = 77,
place = {United States},
year = {Wed Mar 01 00:00:00 EST 2006},
month = {Wed Mar 01 00:00:00 EST 2006}

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  • The usefulness of two-frequency heating for the production of high-charge state high-intensity beams from an ECRIS has been well established. Factors of 2{yields}5 increase in beam currents have been observed accompanied by a shift to higher charge states. The ECRIS at Argonne National Laboratory has been routinely operated utilizing a 14 GHz klystron and a tunable 11-13 GHz traveling wave tube amplifier (TWTA) and the operating characteristics of the source are well known. However, the characteristics of the multi-frequency heated plasma are less well known. Investigations regarding the changes in the source production have been taking place at Argonne Nationalmore » Laboratory. Parameters such as the charge state distribution (CSD), production times and plasma potential have been measured for a multi-frequency heated plasma with emphasis being given to the effect of the frequency gap between the two RF waves. It has been found that the production times decrease in multi-frequency mode with a corresponding increase in the CSD and the overall beam output. At the same time, the plasma potential appears to not change significantly. It has also been found that a larger frequency gap (14.0 and 10.84 GHz), while producing higher charge-state ions, produces less overall beam of the material of interest but reaches equilibrium more quickly when compared to a smaller gap (14,0 and 12.31 GHz). Possible mechanisms for the observed behavior will be discussed.« less
  • The 10.5 GHz electron cyclotron resonance ion source (ECRIS) at Argonne National Laboratory has been utilizing a 10.5 GHz klystron and an 11-13 GHz traveling wave tube amplifier (TWTA) for beam production in two-frequency heating mode. The beam intensities obtained from the source with two-frequency heating have shown a factor of 2 improvement over single-frequency heating for the higher charge states. Following a simple logic that an increased number of resonance zones leads to enhanced source performance, a 14 GHz klystron was added to the source configuration enabling the plasma to be simultaneously excited with three discrete frequencies. In studiesmore » with three-frequency heating when compared to two-frequency heating, the beam intensity for O{sup 7+} increased from 70.4 to 84.2 e{mu}A, Kr{sup 23+} (mass 86, 99.9% enriched) increased from 3.5 to 7.2 e{mu}A, and Xe{sup 28+} (mass 136, 60% enriched) increased from 7.9 to 12.2 e{mu}A. A rf power combiner was added to the TWTA so that it could be driven simultaneously with two frequencies. With the TWTA operating at 10.85 and 12.66 GHz, the intensities of O{sup 6+} increased 80% and O{sup 7+} doubled compared to single-frequency operation, further demonstrating the multiple frequency heating effect except in this instance with a single transmitter.« less
  • A summary of recent developments in ECRIS technology taking place at Argonne National Laboratory is presented in this paper. A pulsed laser for ablation of solid material into the source plasma has been used online with the ATLAS PII-ECRIS and has allowed direct time measurements to be made which verify and quantify sequential, step-by-step ionization taking place in an ECRIS. In addition, during the course of these laser studies a method was discovered which, from an operational viewpoint, represents an important new method for incorporating solid materials into an ECRIS. We also report on a new 14 GHz ECRIS currentlymore » under construction at Argonne. This new ECRIS, along with a new 300 kV high voltage platform and building addition, will further the capabilities of the ATLAS facility by providing the accelerator with a second, independent ECRIS.« less
  • The naturally occurring unpaired electrons in coal provide a unique route for the nondestructive study of coal structure. Electron paramagnetic resonance (EPR), electron-nuclear double resonance (ENDOR), dynamic nuclear polarization (DNP), and electron spin-echo (ESE) techniques use the paramagnetic spins as probes of their environment, and the spins provide information about their immediate chemical surroundings as well as about the nature of more distant regions in the coal. In the context of an ongoing program in our laboratory to better determine the structure and bonding in the organic (maceral) components of whole coals (including Argonne Premium coal samples), coal extracts, andmore » model coal systems by electron magnetic resonance methods (EPR, ENDOR, ESE), we have begun a multifrequency EMR study of coal, with the frequency range spanning nearly 2 orders of magnitude (2-250 GHz), to improve our understanding of the complex magnetic interactions present in the coal material and the origin of these effects in molecular structure and bonding. With this approach, we are developing methods for the elucidation of atomic and molecular structure in coal and other complex, disordered materials. 17 refs., 10 figs., 2 tabs.« less