Analysis of H- Extraction in the Linac4 Negative Ion Source by 2.5D Particle Simulation.

The purpose of this study is to investigate the extraction mechanisms of the H- ions in the Linac4 negative ion source by using an improved two-dimensional in real space and three-dimensional in velocity space Particle in Cell (2D3V-PIC) model, In this model, the following collision processes of the surface produced H-(H-sp) ions have been introduced and the effects of the collisions on H-extraction have been analyzed: elastic (H-sp - H2) and charge exchange (H-sp - H). It is shown that the extracted Hs-sp current increases due to the flow reversal of the H-sp ions caused by these collisions. [ABSTRACT FROM AUTHOR]