Status of the heavy ion beam probe system in the Large Helical Device
- National Institute for Fusion Science (NIFS), 322-6 Oroshi, Toki, Gifu 509-5292 (Japan)
A heavy ion beam probe (HIBP) system has been installed into the Large Helical Device (LHD) to measure the spatial profile of the plasma potential and density fluctuations. The optimization of the HIBP system, especially the beam injector, is described. The negative ion beam is required for the MeV beam production in a tandem accelerator. A sputter-type heavy negative ion source has been developed as an intense Au{sup -} beam source to produce Au{sup +} beams with energy in the MeV range. The extraction electrodes and the Einzel lens system of the ion source have been designed taking into account the beam optics, and installed into the real machine. Throughout the plasma diagnostics on LHD experiments, the consumptions of vaporized caesium and gold target are being characterized for practical operations. In addition, the experimental charge fractions are compared with the theoretical fractions for understanding the charge-changing behavior of Au{sup -} ions and optimizing the fraction of Au{sup +} ions at the exit of the tandem accelerator of the HIBP system.
- OSTI ID:
- 21123715
- Journal Information:
- Review of Scientific Instruments, Vol. 79, Issue 2; Conference: ICIS 2007: 12. international conference on ion sources, Jeju (Korea, Republic of), 26-31 Aug 2007; Other Information: DOI: 10.1063/1.2819323; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
- Country of Publication:
- United States
- Language:
- English
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