Feasibility Study for an Active 238UF6 Gas Target for Photo-Fission Experiments

A series of fission experiments in the actinide region has been started at the superconducting Darmstadt linear accelerator S-DALINAC. For detailed investigations on, e.g., the energy dependence of fission modes, the population of fission isomers, or even the search for parity non-conservation effects (PNC) in the photon-induced fission process of 238U, high luminosities are needed. Increasing target thickness reduces mass and angular resolutions. One possible solution is the utilization of an active gas target containing UF6. In order to test UF6 as an admixture to standard counting gases (e.g. argon) and to study its properties, an ionization chamber has been built at Technische Universität Darmstadt.After testing the chamber with pure argon as a counting gas to evaluate signal quality and to determine the drift velocity, gaseous UF6 was filled into the chamber in steps of one mass-percent uranium for each measurement, where both signal quality and drift velocity at different admixtures have been determined. Up to two percent of uranium in the counting gas one finds that the drift velocity increases with UF6 content, while overall a good signal quality and energy resolution of the ionization chamber is preserved.