Development of a strongly focusing high-intensity He+ ion source for a confined alpha particle measurement at ITER.

A strongly focusing high-intensity He⁺ ion source has been designed and constructed as a beam source for a high-energy He⁰ beam probe system for diagnosis of fusion produced alpha particles in the thermonuclear fusion plasmas. The He⁺ beam was extracted from the ion source at an acceleration voltage of 18–35 kV. Temperature distributions of the beam target were observed with an IR camera. The 1/e-holding beam profile half-width was about 15 mm at optimum perveance (Perv) of 0.03 (I_beam=2.4 A). A beam current about 3 A was achieved at an acceleration voltage of 26.7 kV with an arc power of 10 kW (Perv=0.023). [ABSTRACT FROM AUTHOR]