• T. Iga, S. Hara, T. Seki
  Hitachi, Ltd., Energy and Environmental System Laboratory, Hitachi-shi

A compact and high-proton-yield 2.45 GHz microwave ion source has been developed and tested on an AccSys Model PL-7 linac. The source that has an overall diameter of 115 mm uses permanent magnets and iron yokes. Microwave power was fed to a plasma chamber with a double ridged waveguide via a coaxial cable. A pulsed hydrogen ion beam of 45 mA was extracted from a single 5 mm diameter extraction aperture with a proton fraction of >90 % at 30 keV and a hydrogen gas flow rate of 1 sccm. A 7-MeV proton current out of the linac with the source reached up to 16 mApeak, which exceeds its design value of 15 mApeak. Excellent stability of no more than 1.5 % in both the ion source extraction current and the linac output current was also demonstrated in an 8-hour operation test.