The observed presence of important densities of U ions in our hollow-cathode discharges has prompted our laboratory to investigate in detail the different processes that are responsible for the measured U+ densities. To assess the importance of Penning-type reactions as an ionizing mechanism in our discharges, we have investigated the correlation between metastable Kr and U II ground-state densities in the discharge glow and the decay rates of Kr metastable states in the discharge afterglow of a krypton-sustained uranium hollowcathode discharge. From the results obtained we must conclude that when the discharge is pulsed Penningtype reactions play but a secondary role in the overall ionization of uranium. The main ionization mechanisms appear to be due to electron collisions with U atoms.
© 1984 Optical Society of America
A. Gleizes, P. Bouchard, P. Pianarosa, and J. M. Gagné, "Uranium ionization in a pulsed krypton-sustained hollow-cathode discharge," Appl. Opt. 23, 4532-4538 (1984)