A new plasma potential measurement instrument for plasma ion sources
- Department of Physics, Accelerator Laboratory, University of Jyvaeskylae, P.O. Box 35, FIN-40014, University of Jyvaeskylae (Finland)
A very efficient and fast instrument to measure the plasma potential of ion sources has been developed at the Department of Physics, University of Jyvaeskylae (JYFL). The operating principle of this novel instrument is to apply a decelerating voltage into a mesh located in the beamline of the ion source. The plasma potential is determined by measuring the current at the grounded electrode situated behind the mesh as a function of the voltage. In this article, we will introduce the instrument and the first results. In the experiments, the instrument was connected to the beamline of the JYFL 6.4 GHz electron cyclotron resonance ion source. The plasma potential was measured with different source conditions and it was observed to vary between 30-65 V. The plasma potential tended to increase as the microwave power, or the gas feed rate, was increased. These results are consistent with earlier observations and estimations. It was also noticed that the value of the plasma potential changed when the negative voltage applied to the biased disk at the injection of the ion source was varied. Complementary to optical plasma diagnostics, such an instrument can be used as a very efficient tool to get a precise relationship between plasma conditions and extracted beams.
- OSTI ID:
- 20636616
- Journal Information:
- Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 10 Vol. 75; ISSN 0034-6748; ISSN RSINAK
- Country of Publication:
- United States
- Language:
- English
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