Negative ion production and beam extraction processes in a large ion source (invited)

K. Tsumori, K. Ikeda, H. Nakano, M. Kisaki, S. Geng, M. Wada, K. Sasaki, S. Nishiyama, M. Goto, G. Serianni, P. Agostinetti, E. Sartori, M. Brombin, P. Veltri, C. Wimmer, K. Nagaoka, M. Osakabe, Y. Takeiri, O. Kaneko

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Recent research results on negative-ion-rich plasmas in a large negative ion source have been reviewed. Spatial density and flow distributions of negative hydrogen ions (H-) and positive hydrogen ions together with those of electrons are investigated with a 4-pin probe and a photodetachment (PD) signal of a Langmuir probe. The PD signal is converted to local H-density from signal calibration to a scanning cavity ring down PD measurement. Introduction of Cs changes the slope of plasma potential local distribution depending upon the plasma grid bias. A higher electron density H2plasma locally shields the bias potential and behaves like a metallic free electron gas. On the other hand, the bias and extraction electric fields penetrate in a Cs-seeded electronegative plasma even when the electron density is similar. Electrons are transported by the penetrated electric fields from the driver region along and across the filter and electron deflection magnetic fields. Plasma ions exhibited a completely different response against the penetration of electric fields.
Original languageEnglish
Article number02B936
Pages (from-to)-
JournalReview of Scientific Instruments
Issue number2
Publication statusPublished - 1 Feb 2016
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Instrumentation

Cite this

Tsumori, K., Ikeda, K., Nakano, H., Kisaki, M., Geng, S., Wada, M., Sasaki, K., Nishiyama, S., Goto, M., Serianni, G., Agostinetti, P., Sartori, E., Brombin, M., Veltri, P., Wimmer, C., Nagaoka, K., Osakabe, M., Takeiri, Y., & Kaneko, O. (2016). Negative ion production and beam extraction processes in a large ion source (invited). Review of Scientific Instruments, 87(2), -. [02B936].