The Coulomb Dissociation (CD) cross sections of the stable isotopes 92,94,100Mo and of the unstable isotope 93Mo were measured at the LAND/R3B setup at GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt, Germany. Experimental data on these isotopes may help to explain the problem of the underproduction of 92,94Mo and 96,98Ru in the models of p-process nucleosynthesis. The CD cross sections obtained for the stable Mo isotopes are in good agreement with experiments performed with real photons, thus validating the method of Coulomb Dissociation. The result for the reaction 93Mo(g,n) is especially important since the corresponding cross section has not been measured before. A preliminary integral Coulomb Dissociation cross section of the 94Mo(g,n) reaction is presented. Further analysis will complete the experimental database for the (g,n) production chain of the p-isotopes of molybdenum.

The Coulomb Dissociation (CD) cross sections of the stable isotopes Mo-92,Mo-94,Mo-100 and of the unstable isotope Mo-93 were measured at the LAND/(RB)-B-3 setup at GSI Helmholtzzentrum fur Schwerionenforschung in Darmstadt, Germany. Experimental data on these isotopes may help to explain the problem of the underproduction of Mo-92,Mo-94 and Ru-96,Ru-98 in the models of p-process nucleosynthesis. The CD cross sections obtained for the stable Mo isotopes are in good agreement with experiments performed with real photons, thus validating the method of Coulomb Dissociation. The result for the reaction Mo-93(gamma,n) is especially important since the corresponding cross section has not been measured before. A preliminary integral Coulomb Dissociation cross section of the Mo-94(gamma,n) reaction is presented. Further analysis will complete the experimental database for the (gamma,n) production chain of the p-isotopes of molybdenum.

Photo-dissociation reactions play an important role in p-process nucleosynthesis, which takes place in supernova explosions. Theoretical calculations of isotopic abundances of the p-nuclei require a vast reaction network linking thousands of isotopes, where most of the reaction rates must be derived from the Hauser-Feshbach statistical model. However, as many rates as possible need to be determined experimentally, in order to provide a reliable reference for the calculations. Measuring reaction rates on Mo isotopes is important to explain the problem of the significant underproduction of Mo and Ru in all existing models of p-process nucleosynthesis. Another aspect of the project is to verify the accuracy of the Coulomb dissociation method by comparing our data with experiments performed with real photons at S-DALINAC (TU Darmstadt) and ELBE (FZD) [1].

An experiment was performed using the FRS-LAND setup at GSI to study the dipole strength distributions above neutron separation threshold for neutron-rich Ni isotopes. Measurements, using the same experimental setup, were also carried out to extract single particle occupancies via knockout reactions to investigate the structure and magicity of the neutron-rich Ni isotopes. The status of the data analysis and preliminary results are presented.

We report on first results from experiments using the (α,α′γ) reaction at Eα=136 MeV to investigate bound electric dipole (E1) excitations building the so-called Pygmy Dipole Resonance (PDR) in the semi-magic nucleus 140Ce. The method of (α,α′γ) allows the separation of E1 excitations from states of higher multipolarity, provides an excellent energy resolution and therefore allows a detailed analysis for each single state. Studying bound E1 excitations in α-scattering experiments at intermediate energies becomes feasible for the first time even in nuclei with a high level density. The surprising results of the first experiment on 140Ce point to a splitting of the PDR in this nucleus.

We report on first results from experiments using the (alpha, alpha'gamma) reaction at E alpha = 136 MeV to investigate bound electric dipole (El) excitations building the so-called Pygmy Dipole Resonance (PDR) in the semi-magic nucleus Ce-140. The method of (alpha, alpha'gamma) allows the separation of El excitations from states of higher multipolarity, provides an excellent energy resolution and therefore allows a detailed analysis for each single state. Studying bound E1 excitations in alpha-scattering experiments at intermediate energies becomes feasible for the first time even in nuclei with a high level density. The surprising results of the first experiment on Ce-140 point to a splitting of the PDR in this nucleus.

A concentration of electric-dipole excitations below the particle threshold, which is frequently denoted as the pygmy dipole resonance, has been studied in the semimagic nucleus 140Ce in (alpha, alpha' gamma) experiments at E alpha = 136 MeV. The technique of alpha-gamma coincidence experiments allows the separation of E1 excitations from states of other multipolarities in the same energy region and provides an excellent energy resolution to allow a detailed analysis for each state. The experimental results show that the PDR splits into two parts with different nuclear structure: one part which is excited in (alpha, alpha' gamma) as well as (gamma, gamma') experiments and one part which is excited only in (gamma, gamma').

Excited states in $^{209}\mathrm{Fr}$ were produced following the $^{176}\mathrm{Yb}$($^{37}\mathrm{Cl}$, $4n$) reaction. An excitation function was measured with data taken at 173, 179, and 185 MeV. Recoiling fusion-evaporation products were separated using the SASSYER gas-filled spectrometer. HPGe clover detectors of the YRAST Ball array at the target position and at the focal plane were used to detect prompt and delayed gamma ray decays, providing the first spectroscopic information about prompt and delayed transitions in $^{209}\mathrm{Fr}$. The decay from a proposed $\ensuremath{\pi}{i}_{13/2}$ configuration isomer was observed in $^{209}\mathrm{Fr}$, and its half-life was measured to be 446(14)ns. States above the isomer were also observed.

Lifetime measurements of yrast levels in 162 Yb and 166 Hf were performed using the recoil distance Doppler-shift method in coincidence mode. Excited states in 162 Yb and 166 Hf were populated via the reactions 116 Cd( 50 Ti, 4 n ) and 122 Sn( 48 Ti, 4 n ), respectively. The resulting B ( E 2) values are compared with the X(5) critical point model predictions and interacting boson approximation (IBA) model calculations. The X(5) model provides a reasonable description of the yrast B ( E 2) values in 166 Hf, whereas the IBA fails to reproduce the transition strengths from the higher spin levels. In 162 Yb, some transitions agree with the X(5) predictions while others are more consistent with the predictions of the IBA or a deformed symmetric rotor.

A concentration of electric-dipole excitations below the particle threshold, which is frequently denoted as the pygmy dipole resonance, has been studied in the semimagic nucleus Ce-140 in (alpha, alpha(')gamma) experiments at E-alpha=136 MeV. The technique of alpha-gamma coincidence experiments allows the separation of E1 excitations from states of other multipolarities in the same energy region and provides an excellent energy resolution to allow a detailed analysis for each state. The experimental results show that the PDR splits into two parts with different nuclear structure: one part which is excited in (alpha, alpha(')gamma) as well as (gamma, gamma(')) experiments and one part which is excited only in (gamma, gamma(')).

The knowledge of the cross sections for photodissociation reactions like e.g. (γ, n) of neutron deficient nuclei is of crucial interest for network calculations predicting the abundances of the so-called p nuclei. However, only single cross sections have been measured up to now, i.e., one has to rely nearly fully on theoretical predictions. While the cross sections of stable isotopes are accessible by experiments using real photons, the bulk of the involved reactions starts from unstable nuclei. Coulomb dissociation (CD) experiments in inverse kinematics might be a key to expand the experimental database for p-process network calculations. The approach to test the accuracy of the CD method is explained.

Neutron-induced reaction cross sections on unstable nuclei are inherently difficult to measure due to target activity and the low intensity of neutron beams. In an alternative approach, named the "surrogate" technique, one measures the decay probability of the same compound nucleus produced using a stable beam on a stable target to estimate the neutron-induced reaction cross section. As an extension of the surrogate method, in this paper we introduce a new technique of measuring the fission probabilities of two different compound nuclei as a ratio, which has the advantage of removing most of the systematic uncertainties. This method was benchmarked in this report by measuring the probability of deuteron-induced fission events in coincidence with protons, and forming the ratio P[U-236(d,pf)]/P[U-238(d,pf)], which serves as a surrogate for the known cross section ratio of U-236(n,f)/U-238(n,f). In addition, the P[U-238(d,d(')f)]/P[U-236(d,d(')f)] ratio as a surrogate for the U-237(n,f)/U-235(n,f) cross section ratio was measured for the first time in an unprecedented range of excitation energies.