Negative ion beam extraction in ROBIN

Abstract

The RF based single driver −ve ion source experiment test bed ROBIN (Replica Of BATMAN like source in INDIA) has been set up at Institute for Plasma Research (IPR), India in a technical collaboration with IPP, Garching, Germany. A hydrogen plasma of density 5×1012cm−3 is expected in driver region of ROBIN by launching 100kW RF power into the driver by 1MHz RF generator. The cesiated source is expected to deliver a hydrogen negative ion beam of 10A at 35kV with a current density of 35mA/cm2 as observed in BATMAN.In first phase operation of the ROBIN ion source, a hydrogen plasma has been successfully generated (without extraction system) by coupling 80kW RF input power through a matching network with high power factor (cosθ>0.8) and different plasma parameters have been measured using Langmuir probes and emission spectroscopy. The plasma density of 2.5×1011cm−3 has been measured in the extraction region of ROBIN. For negative hydrogen ion beam extraction in second phase operation, extraction system has been assembled and installed with ion source on the vacuum vessel. The source shall be first operated in volume mode for negative ion beam extraction. The commissioning of the source with high voltage power supply has been initiated.