Preparation of targets by electrodeposition for heavy element studies

For heavy element studies at GSI, lanthanide and actinide targets have been prepared by molecular plating. The deposition occurs from an isopropanolic solution at 1000–1200 V with current densities of a few mA/cm2. Several lanthanide targets have been prepared for test experiments. With natGd deposited on a 10 μm thick Be backing foil a target density of 1100 μg/cm2 could be achieved. Gd-targets were used for the production of α-emitting isotopes of Os, the homologue of hassium (Hs; Z=108), in order to develop a chemical separation procedure for Hs. 248Cm targets with densities up to 730 μg/cm2 have been produced for recent experiments to investigate the chemical behaviour of Hs. Here, a rotating wheel system with a multi-target device has been applied enabling higher beam intensities, compared to a stationary target. The targets were irradiated with a pulsed 26Mg5+ beam applying beam currents up to 6.6 μAelectr. An α-spectroscopic investigation of the irradiated Cm-targets showed that the Cm-material is not evenly distributed over the entire target area. Very often, for heavy element investigations, chemical separation procedures are required to ensure high purity of the deposited actinide materials.