Development and first on-line tests of the RIA gas catcher prototype

Abstract

A new approach to the production of low energy radioactive beams involves the stopping of fast beams produced by fragmentation or in-flight fission in a large gas catcher where the reaction products are thermalized in high-purity helium and extracted as singly charged ions for post-acceleration. This removes the limitation present in standard ISOL techniques for species that are difficult to extract from the target/ion source assembly. This approach will be implemented in the RIA facility. The demonstration of this new technology is a key R&D goal for RIA and a full scale prototype was constructed and tested, both off-line and on-line, at the ATLAS facility at Argonne. The basic operating principles, techniques used for the construction, and results obtained in off-line and on-line tests are presented. The large gas catcher prototype has now been transported to GSI, where fragmentation products at the full RIA energy are available, for its final test.