TARGETS AND ION SOURCES FOR RLB GENERATION AT THE HOLIFIELD RADIOACTIVE ION-BEAM FACILITY

The Holifield Radioactive Ion Beam Facility (HRIBF), now under constru ction at the Oak Ridge National Laboratory, is based on the use of the well-known on-line isotope separator (ISOL) technique in which radioa ctive nuclei are produced by fusion type reactions in selectively chos en target materials by high-energy proton, deuteron, or He ion beams f rom the Oak Ridge Isochronous Cyclotron (ORIC). Among several major ch allenges posed by generating and accelerating adequate intensities of radioactive ion beams (RIBs), selection of the most appropriate target material for production of the species of interest is, perhaps, the m ost difficult. In this report, we briefly review present efforts to se lect target materials and to design composite target matrix/heat-sink systems that simultaneously incorporate the short diffusion lengths, h igh permeabilities, and controllable temperatures required to effect m aximum diffusion release rates of the short-lived species that can be realized at the temperature limits of specific target materials. We al so describe the performance characteristics for a selected number of t arget ion sources that will be employed for initial use at the HRIBF a s well as prototype ion sources that show promise for future use for R IB applications.