Characterization of the arc evaporation of a hot boron cathode

Cathodic are discharge with a hot boron cathode has been characterized by h igh-speed photography, mass spectroscopy and ion energy analysis. During op eration, the cathode surface exhibits an extended molten area in which movi ng cathode spots could be detected by the high-speed cine-camera. This lead s to the conclusion that the hot boron cathode exhibits a mixed are mode in cluding features both of thermionic and spot modes. The charge state distri bution, as well as the kinetic energy of the boron ions emerging from the c athode, were measured and conclusions have been drawn with respect to the u nderlying mechanisms. (C) 1999 Elsevier Science S.A. All rights reserved.