Autoionization spectra and high lying odd parity levels in uranium vapor

Most uranium isotope separation schemes utilizing lasers require a thorough knowledge of the spectroscopy of the atomic vapor system. A critical assessment of economic feasibility of these separation schemes requires measurement of photoionization cross sections, level positions and their transition probabilities, and lifetimes of as large a number of states of the system as is possible. Recent results from high resolution autoionization experiments, designed to identify high lying odd parity levels in uranium vapor, are presented. (U.S.)