Backings and targets for chemical and nuclear studies of transactinides with TASCA

At GSI the gas-filled separator TASCA (TransActinide Separator and Chemistry Apparatus) was set up to investigate the chemical and physical properties of the heaviest elements making use of the highest beam intensities available [www.gsi.de/tasca; M. Schädel, D. Ackermann, A. Semchenkov, A. Türler, GSI Scientific Report 2005, GSI Report 2006-1, p. 262]. Appropriate backings and targets have to be developed.Conceivable backing materials are aluminium, titanium, and carbon. Aluminium backings and titanium backings in different thickness and from different companies are produced by cold rolling. Deposition by resistance heating is applied for carbon backings. For experiments in a chemically active atmosphere, beryllium has to be employed as backing, which is commercially available and produced by cold rolling.The task is to find the best material and thickness for backings to withstand two different processes: the electrodeposition, applied for the production of lanthanide and actinide targets at the Institut für Kernchemie, at the Universität Mainz [K. Eberhardt, et al., Contribution to this conference; D. Liebe, et al., Contribution to this conference], on the one hand, and deposition by thermal evaporation and sputtering on the other.We report on first tests with targets of uranium tetrafluoride (UF4) and metallic uranium on various backings. In addition, the behaviour and durability will be described for the different backing–target combinations in a C-beam and in an Mg beam. For the upcoming beam time U, 208PbS, 144Sm, 154Sm, and Gd are required.