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Title: Electron-cyclotron-resonance ion sources (review)

Abstract

The physical principles are described and a brief survey of the present state is given of ion sources based on electron-cyclotron heating of plasma in a mirror trap. The characteristics of ECR sources of positive and negative ions used chiefly in accelerator technology are presented. 20 refs., 10 figs., 3 tabs.

Authors:
;  [1]
  1. People`s Friendship Univ., Moscow (Russian Federation)
Publication Date:
OSTI Identifier:
135719
Resource Type:
Journal Article
Resource Relation:
Journal Name: Instruments and Experimental Techniques; Journal Volume: 34; Journal Issue: 4; Other Information: PBD: Jan 1992; TN: Translated from Pribory i Tekhnika Eksperimenta; No. 4, 8-18(Jul-Aug 1991)
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ION SOURCES; ELECTRON CYCLOTRON-RESONANCE; DESIGN; ECR HEATING; MULTICHARGED IONS; MAGNETIC MIRRORS

Citation Formats

Golovanivskii, K.S., and Dougar-Jabon, V.D. Electron-cyclotron-resonance ion sources (review). United States: N. p., 1992. Web.
Golovanivskii, K.S., & Dougar-Jabon, V.D. Electron-cyclotron-resonance ion sources (review). United States.
Golovanivskii, K.S., and Dougar-Jabon, V.D. 1992. "Electron-cyclotron-resonance ion sources (review)". United States. doi:.
@article{osti_135719,
title = {Electron-cyclotron-resonance ion sources (review)},
author = {Golovanivskii, K.S. and Dougar-Jabon, V.D.},
abstractNote = {The physical principles are described and a brief survey of the present state is given of ion sources based on electron-cyclotron heating of plasma in a mirror trap. The characteristics of ECR sources of positive and negative ions used chiefly in accelerator technology are presented. 20 refs., 10 figs., 3 tabs.},
doi = {},
journal = {Instruments and Experimental Techniques},
number = 4,
volume = 34,
place = {United States},
year = 1992,
month = 1
}
  • In this article we will recall the main characteristics of electron cyclotron resonance (ECR) discharges for the production of multicharged ions and we will show basic limitations of ECRIS performances using the elementary zero dimension ionization equilibrium model. Then we will present main domains where the ion source characteristics are the limiting factor for the applications. The improvement of the technology of compact ECR ion sources dedicated to applications in special environments like on line isotopic separators or high-voltage platforms will be discussed. Finally, we will describe advanced ion sources projects for future production of very highly charged ions generallymore » connected to superconducting devices. {copyright} {ital 1996 American Institute of Physics.}« less
  • The suitable source for the production of intense beams for high power accelerators must obey to the request of high brightness, stability, and reliability. The 2.45 GHz off-resonance microwave discharge sources are the ideal device to generate the requested beams, as they produce multimilliampere beams of protons, deuterons, and monocharged ions, remaining stable for several weeks without maintenance. A description of different technical designs will be given, analyzing their strength, and weakness, with regard to the extraction system and low energy beam transport line, as the presence of beam halo is detrimental for the accelerator.
  • The major infrastructures of nuclear physics in Europe adopted the technology of electron cyclotron resonance (ECR) ion sources for the production of heavy-ion beams. Most of them use 14 GHz electron cyclotron resonance ion sources (ECRISs), except at INFN-LNS, where an 18 GHz superconducting ECRIS is in operation. In the past five years it was demonstrated, in the frame of the EU-FP5 RTD project called ''Innovative ECRIS,'' that further enhancement of the performances requires a higher frequency (28 GHz and above) and a higher magnetic field (above 2.2 T) for the hexapolar field. Within the EU-FP6 a joint research activitymore » named ISIBHI has been established to build by 2008 two different ion sources, the A-PHOENIX source at LPSC Grenoble, reported in another contribution, and the multipurpose superconducting ECRIS (MS-ECRIS), based on fully superconducting magnets, able to operate in High B mode at a frequency of 28 GHz or higher. Such a development represents a significant step compared to existing devices, and an increase of typically a factor of 10 for the intensity is expected (e.g., 1 emA for medium charge states of heavy ions, or hundreds of e{mu}A of fully stripped light ions, or even 1 e{mu}A of charge states above 50{sup +} for the heaviest species). The challenging issue is the very high level of magnetic field, never achieved by a minimum B trap magnet system; the maximum magnetic field of MS-ECRIS will be higher than 4 or 5 T for the axial field and close to 2.7 T for the hexapolar field. The detailed description of the MS-ECRIS project and of its major constraints will be given along with the general issues of the developments under way.« less
  • Multiple frequency heating is one of the most effective techniques to improve the performance of Electron Cyclotron Resonance (ECR) ion sources. The method increases the beam current and average charge state of the extracted ions and enhances the temporal stability of the ion beams. It is demonstrated in this paper that the stabilizing effect of two-frequency heating is connected with the suppression of electron cyclotron instability. Experimental data show that the interaction between the secondary microwave radiation and the hot electron component of ECR ion source plasmas plays a crucial role in mitigation of the instabilities.
  • Axial and radial diffusion processes determine the confinement time in an ECRIS. It has been demonstrated that a biased disk redirects the ion- and electron currents in the source in such a way that the source performance is improved. This effect is due to a partial cancellation of the compensating currents in the conductive walls of the plasma chamber.In this contribution we present an experiment, where these currents were effectively suppressed by using a metal-dielectric (MD) disk instead of the standard metallic disk in the Frankfurt 14-GHz-ECRIS. Lower values of the plasma potential and higher average charge states in themore » presence of the MD disk as compared to the case of the standard disk indicate that, due to the insulating properties of its dielectric layer the MD disk obviously blocks compensating wall currents better than applying bias to the metallic standard disk.A comparison with results from experiments with a MD liner in the source, covering essentially the complete radial walls of the plasma chamber, clearly demonstrates that the beneficial effect of the liner on the performance of the ECRIS is much stronger than that observed with the MD-disk. In accord with our earlier interpretation, it has to be concluded that the 'liner-effect' is not just the effect of blocking the compensating wall currents but rather has to be ascribed to the unique property of the thin MD liner as a strong secondary electron emitter under bombardment by charged particles.« less