Advertisement

The European Physical Journal D

, Volume 61, Issue 1, pp 107–115 | Cite as

Observations of resonant modes formation in microwave generated magnetized plasmas

  • L. Celona
  • S. Gammino
  • F. Maimone
  • D. Mascali
  • N. Gambino
  • R. Miracoli
  • G. Ciavola
Article

Abstract.

Ion sources have a significant number of applications in accelerator facilities and in industrial applications. In particular, the electron cyclotron resonance ion sources (ECRIS) are nowadays the most effective devices that can feed particle accelerators in a continuous and reliable way, providing high current beams of low and medium charge state ions and lower, but still remarkable, beam current for highly charged ions. In recent years several experiments have shown that the current, the charge states and even the beam shape change by slightly varying the microwave frequency (the so-called frequency tuning effect – FTE). The theoretical explanation of these results is based on the difference in the electromagnetic field pattern over the resonance surface, i.e. that region where the electrons resonantly interact with the incoming wave. In order to be consistent with the experiments, this model requires that standing waves are formed also in presence of a dense plasma. The proof was sought by means of a series of measurements performed with a network analyzer and with a plasma reactor operating at 2.45 GHz, according to the principles of the microwave discharge ion sources (MDIS). The measurements have been carried out with the aim to achieve the electromagnetic characterization of the plasma chamber in terms of possible excited resonant modes with and without plasma, and they reported that resonant modes are excited inside the cavity even in presence of a dense plasma. It was observed that the plasma dynamics strongly depends on the structure of the standing waves that are generated. The measurement of the eigen-frequencies' shifts were carried out for several values of pressure and RF power, thus linking the shift with the plasma density measured by a Langmuir probe. The changes in plasma shape, density and electron temperature have been also monitored for different operating conditions. A strong variation of plasma properties has been observed as a consequence of the introduction of the Langmuir probe inside the resonant cavity, thus demonstrating that the standing wave can be strongly perturbed even by means of relatively small metallic electrodes. The measurements reported hereinafter are relevant also for ECRIS, because they confirm the validity of the theoretical model that describes the frequency tuning.

Keywords

Frequency Shift Resonant Mode Plasma Reactor Resonant Cavity Langmuir Probe 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    L. Celona, G. Ciavola, F. Consoli, S. Gammino, F. Maimone, P. Spaedtke, K. Tinschert, R. Lang, J. Mader, J. Rosbach, S. Barbarino, R.S. Catalano, D. Mascali, Rev. Sci. Instrum. 79, 023305 (2008) CrossRefADSGoogle Scholar
  2. 2.
    R. Geller, F. Bourg, P. Briand, J. Debernardi, M. Delaunay, B. Jacquot, P. Ludwig, R. Pauthenet, M. Pontonnier, P. Sortais, The Grenoble ECRIS status 1987 and proposal for ECRIS scaling, in Proc. 8th Int. Workshop ECR Ion Sources, East Lansing, NSCL report MSUCP-47 (1987), Vol. 1, p. 22 Google Scholar
  3. 3.
    S. Gammino, G. Ciavola, L. Celona, D. Mascali, F. Maimone, IEEE Trans. Plasma Sci. 36, 1552 (2008) CrossRefADSGoogle Scholar
  4. 4.
    F. Maimone, D. Mascali, F. Consoli, S. Barbarino, L. Celona, G. Ciavola, S. Gammino, Simulations and Measurements About the Electromagnetic Properties for the Cylindrical Cavity of the SERSE Ion Source, INFN/TC 06/07 (2006) Google Scholar
  5. 5.
    L. Celona, F. Consoli, S. Barbarino, G. Ciavola, S. Gammino, F. Maimone, D. Mascali, L. Tumino, High Energy Phys. Nucl. Phys. 31, 147 (2007) Google Scholar
  6. 6.
    F. Consoli, L. Celona, G. Ciavola, S. Gammino, F. Maimone, S. Barbarino, R.S. Catalano, D. Mascali, Rev. Sci. Instrum. 79, 02A308 (2008) Google Scholar
  7. 7.
    S. Gammino, G. Ciavola, L. Celona, S. Passarello, L. Ando, F. Consoli, D. Mascali, F. Maimone, Czech J. Phys. 56, 223 (2006) CrossRefGoogle Scholar
  8. 8.
    S. Gammino, D. Mascali, L. Celona, G. Ciavola, F. Maimone, S. Barbarino, N. Gambino, R. Miracoli, F. Samperi, Diagnostics and preliminary operations of a microwave discharge plasma reactor for complex molecules dissociation, Proc. of 34th EPS Conference on Plasma Physics (Warsaw, July 2007) Google Scholar
  9. 9.
    D. Mascali, N. Gambino, R. Miracoli, S. Barbarino, S. Gammino, L. Torrisi, F. Maimone, L. Tumino, Radiat. Eff. Defects Solids 163, 471 (2008) CrossRefADSGoogle Scholar
  10. 10.
    Hiden ESPion-Advanced Langmuir Probe for Plasma Diagnostics, http://www.hidenanalytical.com/, accessed in September 2010
  11. 11.
    B. Agdur, B. Enander, J. Appl. Phys. 33, 575 (1962) CrossRefADSGoogle Scholar
  12. 12.
    S.J. Buchsbaum, S.C. Brown, Phys. Rev. 106, 196 (1957) CrossRefADSGoogle Scholar
  13. 13.
    J. Asmussen, R. Malhtvarpu, J.R. Hamann, C. Park, Proc. IEEE 62, 109 (1974) CrossRefGoogle Scholar
  14. 14.
    J.L. Shohet, A.J. Hatch, J. Appl. Phys. 41, 2610 (1970) CrossRefADSGoogle Scholar
  15. 15.
    D. Mascali, Ph.D. thesis, University of Catania, 2009 Google Scholar
  16. 16.
    D.M. Pozar, Microwave Engineering (Wiley, New York, 1998) Google Scholar
  17. 17.
    F. Consoli, S. Barbarino, L. Celona, G. Ciavola, S. Gammino, D. Mascali, Radiat. Eff. Defects Solids 160, 467 (2005) CrossRefADSGoogle Scholar
  18. 18.
    S. Gammino, J. Sijbring, A.G. Drentje, Rev. Sci. Instrum. 63, 2872 (1992) CrossRefADSGoogle Scholar

Copyright information

© EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg 2010

Authors and Affiliations

  • L. Celona
    • 1
  • S. Gammino
    • 1
  • F. Maimone
    • 1
  • D. Mascali
    • 1
  • N. Gambino
    • 1
  • R. Miracoli
    • 1
  • G. Ciavola
    • 1
  1. 1.Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali del SudCataniaItaly

Personalised recommendations