High Voltage Negative Ion Beam Injector for Tandem Accelerator

An electrostatic vacuum-insulated tandem accelerator, delivering 2 divided by 2.5 MeV protons with continuous accelerated current more than 5 mA for the BNCT study is under operation at Budker Institute of Nuclear Physics since 2006. To increase the ion beam current, injected to tandem the injector scheme with negative ions acceleration to energy of 150 keV was constructed and studied. It consists of the CW surface plasma negative ion source, of the bending magnet, providing the ion beam focusing and purifying from the concomitant harmful impurities, and of acceleration tube, which pre-accelerates the ion beam before injection to tandem. The source, its subsystems and bending magnet are installed at the high-voltage platform. The features of the new injector and the first results on 15 mA negative ion beam production and acceleration to energy up to 150 keV is discussed.