Analysis of electron energy distribution of an arc-discharge H(-) ion source with Monte Carlo simulation.

For optimization and accurate prediction of the amount of H(-) ion production in negative ion sources, analysis of electron energy distribution function (EEDF) is necessary. We developed a numerical code which analyzes EEDF in the tandem-type arc-discharge source. It is a three-dimensional Monte Carlo simulation code with the effects of cusp, filter, and extraction magnets. Coulomb collision between electrons is treated with Takizuka's model and several inelastic collisions are treated with null-collision method. We applied this code to the JAEA 10 ampere negative ion source. The numerical result shows that the order of electron density is in good agreement with experimental results. In addition, the obtained EEDF is qualitatively in good agreement with experimental results.