Neutron-induced fission cross sections for 242,243Cm and 241Am have been obtained with the surrogate reaction method. Recent results for the neutron-induced cross section of 243Cm are questioned by the present data. For the first time, the 242Cm cross section has been determined up to the onset of second-chance fission. The good agreement at the lowest excitation energies between the present results and the existing neutron-induced data indicates that the distributions in spin and parity of states populated with both techniques are similar

174Yb(3He,αγ )173Yb* and 174Yb(3He,pγ )176Lu*, respectively. For the first time, the gamma-decay probabilities have been obtained with two independent experimental methods based on the use of C6D6 scintillators and Germanium detectors. Our results for the radiative-capture cross sections are several times higher than the corresponding neutron-induced data. To explain these differences, we have used our gamma-decay probabilities to extract rather direct information on the spin distributions populated in the transfer reactions used. They are about two times wider and the mean values are 3 to 4 ¯h higher than the ones populated in the neutron-induced reactions. As a consequence, in the transfer reactions neutron emission to the ground and first excited states of the residual nucleus is strongly suppressed and gamma-decay is considerably enhanced

The γ -ray strength function in the quasicontinuum has been measured for [231][232][233] 232,233 Pa, and 237-239 U using the Oslo method. All eight nuclei show a pronounced increase in γ strength at ω SR ≈ 2.4 MeV, which is interpreted as the low-energy M1 scissors resonance (SR). The total strength is found to be B SR = 9-11 μ 2 N when integrated over the 1-4 MeV γ -energy region. The SR displays a double-hump structure that is theoretically not understood. Our results are compared with data from (γ , γ ) experiments and theoretical sum-rule estimates for a nuclear rigid-body moment of inertia.

The electron-ion scattering experiment ELISe is part of the installations envisaged at the new experimental storage ring at the international Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany. It offers an unique opportunity to use electrons as probe in investigations of the structure of exotic nuclei. The conceptual design and the scientific challenges of ELISe are presented.

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We investigated the 238 U(d,p) reaction as a surrogate for the n + 238 U reaction. For this purpose we measured for the first time the gamma-decay and fission probabilities of 239 U* simultaneously and compared them to the corresponding neutron-induced data. We present the details of the procedure to infer the decay probabilities, as well as a thorough uncertainty analysis, including parameter correlations. Calculations based on the continuum-discretized coupledchannels method and the distorted-wave Born approximation (DWBA) were used to correct our data from detected protons originating from elastic and inelastic deuteron breakup. In the region where fission and gamma emission compete, the corrected fission probability is in agreement with neutron-induced data, whereas the gamma-decay probability is much higher than the neutroninduced data. We have performed calculations of the decay probabilities with the statistical model and of the average angular momentum populated in the 238 U(d,p) reaction with the DWBA to interpret these results.

Particle-γ coincidences have been measured to obtain γ -ray spectra as a function of excitation energy for [231][232][233] Th and 237-239 U. The level densities, which were extracted using the Oslo method, show a constant temperature behavior. The isotopes display very similar temperatures in the quasicontinuum, however, the evenodd isotopes reveal a constant entropy increase S compared to their even-even neighbors. The entropy excess depends on available orbitals for the last unpaired valence neutron of the heated nuclear system. Also, experimental microcanonical temperature and heat capacity have been extracted. Several poles in the heat capacity curve support the idea that an almost continuous melting of Cooper pairs is responsible for the constant-temperature behavior.

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