(FT/P5-2) Development of Strongly Focused High-Current-Density Ion Beam System and Its Application for the Alpha Particle Measurement in ITER
1) National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
2) Tohoku University, 6-6-01-2 Aoba, Aramaki, Sendai 980-8579, Japan
3) University of Wisconsin – Madison, Madison, WI 53706, USA
Abstract. Strongly focused and high-current density ion beam system was successfully developed using large concave electrodes. The beam with a diameter of 345 mm at the electrode is focused to a diameter of ∼36 mm at the focal point with a small total divergence angle of about 1.6 deg. In the cases of H+, He+ and HeH+ beams of ∼25 keV, it is estimated that the extracted ion current density achieves as high as ∼190, ∼86 and ∼13 mA/cm2, respectively. The HeH+ beam of ∼25 keV can be considered as a primary beam of a diagnostic helium neutral beam of ∼1-2 MeV for the alpha particle measurement in ITER, and it is demonstrated for the first time that the current density level of HeH+ beam is sufficient for this purpose.
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