An advanced ISOL facility based on ATLAS

The Argonne concept for an accelerator complex for efficiently producing high-quality radioactive beams from an ion source energy up to 6-15 MeV/u is described. The Isotope-Separator-On-Line (ISOL) method is used. A high-power $9 driver accelerator produces radionuclides in a target that is closely coupled to an ion source and mass separator. By using a driver accelerator which can deliver a variety of beams and energies the radionuclide production mechanisms $9 can be chosen to optimize yields for the species of interest. To effectively utilize the high beam power of the driver two-step target /ion source geometries are proposed: (1) Neutron production with intermediate energy deuterons on $9 a primary target to produce neutron- rich fission products in a secondary /sup 238/U target, and (2) Fragmentation of neutron-rich heavy ion beams such as /sup 18/O in a target/catcher geometry. Heavy ion beams with total energies in $9 the 1-10 GeV range are also available for radionuclide production via high-energy spallation reactions: at the present time R&D is in progress to develop superconducting resonator structures for a driver linac to cover the energy $9 range up to 100 MeV per nucleon for heavy ions and 200 MeV for protons. The post accelerator scheme is based on using existing ISOL-type 1+ ion source technology followed by CW Radio Frequency Quadrupole (RFQ) accelerators and $9 superconducting linacs including the present ATLAS accelerator. A full-scale prototype of the first-stage RFQ has been successfully tested with RF at full design voltage and tests with ion beams are in progress. A benchmark beam, $9 /sup 137/Sn @ 7 MeV/u, requires two stripping stages, one a gas stripper at very low velocity after the first RFQ section, and one a foil stripper at higher velocity after a superconducting- linac injector. (36 refs).