The Effusive-Flow Properties of Target/Vapor-Transport Systems for Radioactive Ion Beam Applications

We have developed a fast valve system (closing time ∼100 μs) that can be used to accurately measure the effusion times of various species through arbitrary geometry and size vapor-transport systems with and without target material in the reservoir. The effusive-flow times are characteristic of the system and thus serve as figures of merit for assessing the quality of a given vapor transport system as well as for assessing the permeability properties of a given target design. This article presents effusive-flow data measured with the fast valve system for noble gases flowing through a target reservoir and ion source system routinely used to generate radioactive species at the HRIBF. We determine added delay times associated with compressed reticulated-vitreous-carbon-foam (RVCF) disks, which are used for target coating matrices.