Characterization of a novel alkali metal and transition metal plasma source

Summary form only given, as follows. Characterization studies of a metal vapor plasma, and potentially an ion source, are reported. The source is well suited to solids having dielectric and thermal properties that permit their rapid heating by a high-frequency (2-3 GHz) signal. When the solid is properly placed in a resonant cavity, the conductively and dielectrically heated surface emits a vapor stream, which is then ionized in the near-surface region, yielding a metal-ion-rich plasma. Plasmas have been produced from two alkali metal halides, NaCl and KBr, as well as from graphite, titanium dioxide, and iron oxide. The power densities involved are characteristic of high-frequency plasmas and range from 1 to 30 W/cm/sup 3/. The factor of two or three difference between the ionization potentials of the metals and of the halides or oxygen results in an enrichment of the metal-ion content of the plasma and in the presence of the halides or oxygen as atoms rather than ions.<>