Production of Neutron-Rich Isotopes from UC Targets for RIB Development

The Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory (ORNL) provides radioactive beams for research in nuclear physics. An essential function is to produce a variety of radioactive species to meet the intensity, energy, and purity requirements of specific experiments. A primary production method has been proton-induced fission of uranium. The principal targets employed have been constructed at ORNL in the form of uranium carbide (UC) bound within a matrix of carbon fibers ($\sim $0.8-1.3 g/cm$^{3})$. Recently, pressed-powder targets of uranium carbide, fabricated at ANL from uranium oxide (2.61 g/cm$^{3})$ or uranium carbide (6.03 g/cm$^{3})$, have been used. These pellets (2.61 and 6.03 g/cm$^{3}$, respectively) produced yields in ratios of approximately 1 to 10 compared to the fiber materials, with the amount of increase differing by chemical element. Deuteron-induced fission on an ANL pellet has also been investigated with, however, no significant improvement in yields observed. Possible causes for the differing results will be discussed. \textit{Supported in part by the U. S. Department of Energy}