NEW RESULTS ON LOW-ENERGY FISSION WITH HIGH-ENERGY RNB

At the fragment separator (FRS) at GSI Darmstadt fission studies with a number of secondary beams produced by fragmentation of a 1 A.GeV U-2 38 beam have been performed. Fission-in-flight was induced in a second ary lead target at average secondary-beam kinetic energies of about 40 0 MeV.A. By measuring the velocities and the energy losses of both fis sion fragments their nuclear charges could be determined. From the dat a, fission-fragment charge distributions for electromagnetic-induced f ission in lead at an average excitation energy of 10 MeV were extracte d. Our method offers the possibility to vary the A/Z-ratio of the seco ndary-beam particle over a wide range and thus to investigate the prot on even-odd effect as well as the transition from symmetric fission to asymmetric fission in a region of the chart of the nuclides which was difficult to reach in previous fission studies.