Search

Fission fragment mass distributions were measured in the heavy-ion induced fission using 238U target nucleus. The mass distributions changed drastically with incident energy. The results are explained by a change of the ratio between fusion and qasifission with nuclear orientation. A calculation based on a fluctuation dissipation model reproduced the mass distributions and their incident energy dependence. Fusion probability was determined in the analysis. Evaporation residue cross sections were calculated with a statistical model in the reactions of 30Si+238U and 34S+238U using the obtained fusion probability in the entrance channel. The results agree with the measured cross sections of 263,264Sg and 267,268Hs, produced by 30Si+238U and 34S+238U, respectively. It is also suggested that the sub-barrier energies can be used for heavy element synthesis.

The production of 283112 in 48Ca induced nuclear reactions was investigated using physical and chemical separation techniques. In the reaction 48Ca on 238U, four events were registered at the SHIP velocity filter. The mean atomic mass of the evaporation residues (EVR)

The use of metallic lead or bismuth targets is limited at high beam currents due to their low melting point. In order to increase the intensity for irradiation, we investigated chemical compound targets with higher melting temperature. The properties of these targets are promising for further increase of the sensitivity in experiments searching for superheavy elements. The target material is controlled in each step of the production process as well as after the irradiation by optical microscopy, weighing, scanning electron microscopy (SEM), and energy‐dispersive x‐ray analysis (EDX). In some cases also wavelength dispersive x‐ray analysis (WDX), and Atomic Force Microscopy (AFM) are applied. We report on the synthesis of the target material, the production of the targets and their application in heavy‐ion experiments.

We report on the status of target development for the heavy-element program at GSI, namely for the SHIP experiment. We present some recent results in enhancing the durability of the targets irradiated with the more and more intense heavy-ion beams. The enhancement of the beam intensity is necessary in order to keep beam times at reasonable length despite cross sections in the picobam region. We synthesised new compound targets on 208Pb-basis with significantly higher melting temperatures and built up a target monitoring system. To investigate the high-current targets and develop an active cooling system we built up a test bench for offline experiments.