H- beam extraction from a cesium seeded field effect transistor based radio frequency negative hydrogen ion source

H- beam was successfully extracted from a cesium seeded ion source operated using a field effect transistor inverter power supply as a radio frequency (RF) wave source. High density hydrogen plasma more than 10(19) m(-3) was obtained using an external type antenna with RF frequency of lower than 0.5 MHz. The source was isolated by an isolation transformer and H- ion beam was extracted from a single aperture. Acceleration current and extraction current increased with the increase of extraction voltage. Addition of a small amount of cesium vapor into the source enhanced the currents. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3684720]