A slab-shaped electron cyclotron resonance ion beam source for in-line running target treatments

Abstract

The possibility of industrial surface treatments of broad metallic rolls by appropriate ion beams has motivated our study of an immersed electron cyclotron resonance slab-shaped ion source composed of a number of elementary microwave modules fed in parallel through a linear power divider. We describe the performances of a single module implemented by a 45-mm-height ionization chamber of 80×15 mm cross section surrounded by a set of permanent magnets in a multipole configuration. A current density of 5 mA/cm2, uniform to within 10% over a 60 mm width, has been obtained for argon as well as for oxygen and nitrogen under a 500 W input power and a gas pressure of 5–8×10−3 mbar in the ionization chamber. Moreover, we have investigated the case of the non-normal incidence of the ion beam onto the running target. For 30° and 60° incidence angles with respect to the normal, the current density loss is 15% and 25%, respectively.