Development of an H ion source for the high intensity proton Linac

Oguri, Hidetomo  ; Okumura, Yoshikazu; Hasegawa, Kazuo; Namekawa, Yuya*; Shimooka, Takashi*

At JAERI, a high intensity proton accelerator with a beam power of 1 MW has been proposed to pursue the nuclear-particle physics, materials and life sciences and R&D for nuclear transformation. A negative hydrogen ion source for the accelerator is required to extract a peak beam current of more than 60 mA with a normalized emittance of 0.15 pimm.mrad (rms). We have designed and tested a volume production type negative ion source to accumulate experimental data to fulfill the requirement for the accelerator. The source plasma is produced by an arc discharge using tungsten filaments. The cesium vapor is introduced into the arc chamber to enhance the beam current. The beam extractor consists of three electrodes with a single aperture of 8 mm in diameter. The negative ion beam current of 40 mA was achieved with a duty factor of 5 % at the beam energy and arc discharge power of 70 keV and 30 kW, respectively. The beam current increased linearly with the arc power in the cesium operation. The beam test by using a more powerful arc power supply is in progress.