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 dipole strength distribution of Se-80 was studied in a photon-scattering experiment by using bremsstrahlung produced with an electron beam of energy 11.5 MeV at the linear accelerator ELBE. We identified 180 gamma transitions up to an energy of 9.6 MeV, and analyzed the strength in the quasicontinuum of the spectrum. Simulations of statistical gamma-ray cascades were performed to estimate intensities of inelastic transitions and to correct the intensities of the ground-state transitions for their branching ratios. The photoabsorption cross section below the neutron-separation energy derived in this way was combined with the photoabsorption cross section obtained from an earlier (gamma,n) experiment and used as an input for the calculation of Se-79(n,gamma) reaction rates on the basis of the statistical reaction model.

Jan Glorius †1 ,M. Knörzer 1, S. Müller 1, N. Pietralla 1, A. Sauerwein 1,2,3, K. Sonnabend 1, C. Wälzlein 1, M. Wiescher 3 1Institut für Kernphysik, Technische Universität Darmstad t, Schlossgartenstr. 9, D-64289 Darmstadt, Germany 2Institut für Kernphysik, Universität zu Köln, Zülpicher St . 77, D-50937 Cologne, Germany 3Department of Physics, University of Notre Dame, Notre Dame , IN 46556-5670, U.S.A. E-mail: glorius@ikp.tu-darmstadt.de

Competition between excited core states and 1h̄ω single-particle excitations at comparable energies in 207Pb from photon scattering N. Pietralla a,b,c,∗, T.C. Li b, M. Fritzsche a, M.W. Ahmed d, T. Ahn a,b,c, A. Costin a,b,c, J. Enders a, J. Li e, S. Müller a, P. von Neumann-Cosel a, I.V. Pinayev e, V.Yu. Ponomarev a, D. Savran a, A.P. Tonchev d, W. Tornow d, H.R. Weller d, V. Werner f, Y.K. Wu e, A. Zilges c

High-resolution photon scattering experiments have been performed on the nucleus 45Sc at the Darmstadt superconducting electron accelerator S-DALINAC using bremsstrahlung beams with end point energies of 5.0 and 7.0MeV. Energies, absolute cross-sections and decay widths of 50 states, most of them previously unknown, have been determined. The results are compared to (γ,\( \gamma{^\prime}\)) experiments on the neighbouring closed proton shell isotope 44Ca .

This report summarizes experiments performed on Dy-164 using photon scattering techniques. The scissors mode in Dy-164 has been reinvestigated using unpolarized photons from bremsstrahlung and polarized photons from a free electron laser. The current experiments lead to the observation of a new decay mode of the scissors mode in well-deformed rotors.

The neutron capture cross section of the unstable nucleus Re-186 is studied by investigating the inverse photodisintegration reaction Re-187(gamma, n). The special interest of the s-process branching point Re-186 is related to the question of possible s-process contributions to the abundance of the r-process chronometer nucleus Re-187. We use the photoactivation technique to measure photodisintegration rates. Our experimental results are in good agreement with two different statistical model calculations. Although the cross sections predicted by both models for the inverse reaction Re-186(n, gamma) is too low to remove the overproduction of Os-186; the two predicted neutron-capture cross sections differ by a factor of 2.4; this calls for future theoretical study.

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.

The 100 % polarized photon beam at the High Intensity gamma-ray Source (HIgS) at Duke University has been used to determine the parity of six dipole excitations between 2.9 and 3.6 MeV in the deformed nuclei 172,174 Yb in photon scattering (g,g') experiments. The measured parities are compared with previous assignments based on the K quantum number that had been assigned in Nuclear Resonance Fluorescence (NRF) experiments by using the Alaga rules. A systematic survey of the relation between gamma-decay branching ratios and parity quantum numbers is given for the rare earth nuclei.

An experimental method developed at the S-DALINAC accelerator for the study of (gamma,n) reactions related to nucleosynthesis during the astrophysical p- and S process is presented. The direct determination of (gamma,n)-reaction rates under astrophysical conditions, as well as a method to correct (n,gamma) cross sections based on the inverse reaction, are presented. A comparison of experimentally derived (gamma,n)-reaction rates to statistical model calculations is also shown.

The use of tunable coplanar stuhline-filters on a ferroelectric thick film has heen investigated For phase-shifter applications at rmm temperature. Circuits with one to three shorted, tunable low-impendance quarter-wavelength stubs have been designed and realized on Al2O3 substrate with a 3.2μm porous layer of screen-printed Ba0.6Sro4Tio3 (EST). A phase shift of 31° (one element), 69° (two elemens) and 109° (three elements) could he achieved at 12.5GHz. Typical bandwidths (s11 ~ <-10 dB)re between 7% and 11%. The Figure-of-Merit amounts to about 1O°dB.