A fast effusive-flow vapor-transport system for ISOL-based radioactive ion beam facilities

In order to generate useful beam intensities of short-lived radioactive isotopes for nuclear and nuclear-astrophysics research at ISOL-based radioactive ion beam facilities, delay times associated with diffusion release from target materials and effusive-flow transport from production targets to ion sources must be reduced to as low as practically achievable levels. A fast vapor-transport system has been conceived that reduces effusive-flow times from target to ion source by>2 orders of magnitude over those of conventional transport systems used at CERN-ISOLDE and the Holifield Radioactive Ion Beam Facility. For target material thicknesses of ∼1 μm, the new system permits the generation of useful RIB intensities of species with lifetimes of a few tens of milliseconds to a few seconds and target/species combinations with diffusion coefficients in the range, 10−8⩾D(cm2/s)⩾10−10.