Speaker
Description
Fundamental data on surface reflection and adsorption/implantation are necessary for understanding edge plasma physics to design future fusion reactor components. A large divergent angle arising from low energy ion beam transport reduces signal intensity to make study on fundamental processes more difficult. A 40 mm diameter, 70 mm long compact ion source is being developed aiming at substantial reduction in beam travel distance.The source structure enables the replacement of the wall material to see the effect upon fractions of hydrogen molecular ions in the extracted beam. The ion source is attached near a rotating target in vacuum to collect data on surface reflection of hydrogen.The developed source has already produced several tens of nA of $\rm H^{+}_2$ and $\rm H^{+}_3$ ion beam current at energy lower than several hundred volts through a 1 mm diameter hole, while further enhancement in beam current density and reduction of beam energy are being attempted.The source material should have different recombination coefficients and changes molecular spices in the ion source plasma. The effect is being investigated for $\rm H^{+}_3$ in the extracted beam.
