Numerical analysis of the production profile of [H.sup.0] atoms and subsequent [H.sup.-] ions in large negative ion sources

A three-dimensional Monte Carlo transport code was used to numerically analyze the effect of the [H.sup.0] atom production profile on the surface production profile of the [H.sup.-] ions and to clarify the origin of the nonuniformity of the [H.sup.-] ion beam. The result indicated that [H.sup.0] atom production is locally enhanced in the high-electron-temperature region where electrons in the high-energy tail are localized.