Two-frequency plasma heating in a high charge state electron cyclotron resonance ion source

Xie, Z. Q.; Lyneis, C.M.

doi:10.1063/1.1145372

Cited by 57 publications

(36 citation statements)

References 6 publications

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“…13 and 14. Thus, the ''volume'' effect has been clearly demonstrated in these experiments as well as those of Xie and Lyneis 5. …”

mentioning

confidence: 63%

“…Thus, whenever the ECR zones are increased, the charge-state spectra are expected to shift from lower to higher values, exactly in keeping with the present results, as well as those of Xie and Lyneis. 5 Conventional minimum-B ECR ion sources utilize single-frequency microwave power supplies to generate and maintain plasmas in these sources. Since these power supplies have bandwidths of 20-50 MHz, the ECR zones are thin ''surfaces'' which surround their axes of symmetry intersecting them at two points, as indicated in the schematic drawing of the Oak Ridge National Laboratory ͑ORNL͒ Caprice ECR ion source, 6 shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

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Enhancing the performances of traditional electron cyclotron resonance ion sources with multiple-discrete-frequency microwave radiation

Alton

Meyer

Liu

et al. 1998

Review of Scientific Instruments

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The performances of electron cyclotron resonance (ECR) ion sources, in terms of high-charge-state yields and intensities within a particular charge state, can be enhanced by increasing the physical sizes of the ECR zones in relation to the sizes of their plasma volumes. The creation of a large ECR plasma “volume” permits coupling of more power into the plasma, resulting in the heating of a much larger electron population to higher energies, the effect of which is to produce higher charge-state distributions and higher intensities within a particular charge state than possible in present forms of the ECR source. The ECR plasma “volumes” of traditional B-minimum ECR sources can be increased by injecting broadband microwave radiation (multiple-discrete-frequency, variable frequency, or broad-band-width frequency microwave radiation) derived from standard klystron, gyrotron, or traveling-wave-tube (TWT) technologies (frequency domain). To demonstrate that the frequency domain technique can be used to enhance the performance of a traditional B-minimum ECR ion source, comparative studies were made to assess the relative performances of the Oak Ridge National Laboratory Caprice ECR ion source, in terms of multiply charged ion-beam generation capabilities, when excited with high-power, single-frequency, or multiple-discrete-frequency microwave radiation, derived from standard klystron and/or TWT technologies. These studies demonstrate that the charge-state populations for Ar q+ and Xeq+ move toward higher values when excited with two and three discrete-frequency, microwave power compared to those observed when single-frequency microwave power is used. For example, the most probable charge state for Xe is increased by one charge-state unit while the beam intensities for charge states higher than the most probable are increased by factors of ∼3 compared to those observed for single-frequency plasma excitation. The results of these measurements along with details on the modifications to the injection system required to couple the microwave radiation into the plasma volume of the Caprice source will be presented in this report.

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“…13 and 14. Thus, the ''volume'' effect has been clearly demonstrated in these experiments as well as those of Xie and Lyneis 5. …”

mentioning

confidence: 63%

Section: Introductionmentioning

confidence: 99%

Enhancing the performances of traditional electron cyclotron resonance ion sources with multiple-discrete-frequency microwave radiation

Alton

Meyer

Liu

et al. 1998

Review of Scientific Instruments

View full text Add to dashboard Cite

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“…The experiments also suggest that the instabilities can be mitigated by 2-frequency heating. 5,6 An experimental setup has been developed to study plasma induced photoelectron emission from different plasma chamber materials. The experiments have shown that the effect could have a contribution to properties of hydrogen ion source plasma.…”

Section: Experimental Plasma Researchmentioning

confidence: 99%

Ion source research and development at University of Jyväskylä: Studies of different plasma processes and towards the higher beam intensities

Koivisto

Kalvas

Tarvainen

et al. 2015

Review of Scientific Instruments

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“…There have been various attempts to increase beam intensity and charge state. The multi-frequency heating has proved an effective way to increase both the number and width of the ECR zone [3]. Wall coating [4] in the inner wall of plasma chamber was attempted in order to supply more electrons.…”

Section: Introductionmentioning

confidence: 99%

Design of a compact ECR ion source with Ku band

Lee

Kwon²,

Tojyo³

et al.

Proceedings of the 1999 Particle Accelerator Conference (Cat. No.99CH36366)

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The electron cyclotron resonance (ECR) ion sources are increasingly popular for producing highly charged ions. With worldwide proposals to build the Isotope Seperator OnLine (ISOL) facility being at hand, it becomes important to design a high efficiency ion source as a charge breeder for the secondary beam. A novel type of ECR ion source based on a flat magnetic field configuration has been proposed by Alton et al. [1,2] This source provides a large, on-axis electron cyclotron resonance region, "ECR-volume". Due to a larger ECR zone, absorptivity of microwave power into plasma is much increased, thereby electron becomes so hot. And hot electron population of the plasma could result in higher charge states and higher beam intensity. Two sloenoids are used to produce axial mirror magnetic field. Twelve permanent magnets (NdFeB) are designed for confining the hot electrons in the radial direction. Moreover, specially designed iron yokes are added to create the flat central field region. The single injected microwave frequency is tunable in the range of 6.45 to 14 GHz covering the range of the Ku band. We shall present the design report concerning the field mapping obtained by POISSON and OPERA-3D together with and mechanical design.

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Two-frequency plasma heating in a high charge state electron cyclotron resonance ion source

Cited by 57 publications

References 6 publications

Enhancing the performances of traditional electron cyclotron resonance ion sources with multiple-discrete-frequency microwave radiation

Enhancing the performances of traditional electron cyclotron resonance ion sources with multiple-discrete-frequency microwave radiation

Ion source research and development at University of Jyväskylä: Studies of different plasma processes and towards the higher beam intensities

Design of a compact ECR ion source with Ku band

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