Author: Stiebing, K.E.
Paper Title Page
TUYO03 Secondary-electron-enhanced Plasma as an Alternative to Double/Variable-frequency Heating in ECRIS 22
 
  • K.E. Stiebing
    IKF, Frankfurt-am-Main, Germany
  • S. Dobrescu, L. Schächter
    IFIN, Magurele- Bucuresti, Romania
 
  As "double frequency heating" (DFH) now has become the method of choice to optimize the output from the newest generation ECRIS, it was a challenge to compare this method with the comparatively cheap method of "metal dielectric" (MD) structures introduced into the plasma chamber, which has also proven to strongly enrich the plasma with electrons that are effectively trapped and heated. Two RF-systems have been launched to the 14 GHz ECRIS, however, not allowing RF-differences as large as 1.5 GHz as demanded for DFH. Therefore the source was operated in a "frequency tuning" mode (FT) by optimizing the frequency difference by the output of Ar14+ ions. The data without and with MD-configuration are compared and related to data for the DFH. On the basis of Bremsstrahlung radiation spectroscopy and charge state analysis, it turned out that the FT-mode does not change the source performance substantially. The measured effects are in the order of 20% to 30% as reported elsewhere. In contrast to this, the enhancement gained by the MD method is much higher. The measured enhancement ratios even surpass those reported for real double frequency heating.  
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