Refractory beams at ISOLDE - A concept for a fission recoil target

We propose here an advanced target design for ISOL (isotope separation on-line) facilities, in which diffusion through condensed matter can be fully avoided. Instead of diffusion, we make use of the recoil momentum, which allows fission fragments to propagate through and emerge from thin uranium foils. The recoils are thermalized in a reactive gas and form volatile compounds in-situ. Subsequently, the reactive gas is removed by cryogenic gas separation. The system is evacuated while the carbonyl compounds are retained on a cooling trap. After removal of the excess gas, the volatile compounds are fed into the ion source by warming up the cooling trap. A compound class that appears well suited for in-situ volatilization is that of metal carbonyl complexes. While carbonyl compounds open up new perspectives in the development of refractory beams, they are delicate compounds. Decomposition on hot surfaces, by electron beams, plasmas and UV-light is expected, which needs to be considered not only in the target design, but also in the choice of the ion source. Within this work, simulations have been conducted aiming at the estimation of attainable yields. This document is made up of an article and a poster.