Gas Flow Influence on Negative Hydrogen Ion Generation within the Microwave-driven Negative Ion Source*

H ion was generated through two processes within a volume Csfree source. The density of molecule hydrogen gas will impact on the electron temperature within the primary discharge chamber that will influence the population of vibrational excited H2. Within the extraction region, the interaction between molecule hydrogen and H ion will is cause the dissociation of negative ion. To better understand the gas flow influence on H ion generation within a volume negative ion source, a new Cs-free volume microwave-driven Hsource body with two gas inlets was developed at Peking University (PKU). Experiment on gas flow and gas pressure distribution within the plasma chamber was carried out with this source body. In the meantime a two dimensional (2D) model for gas flow was developed. Details will be presented in this paper.