C. Langer

Neutron capture cross section of unstable 63Ni: implications for stellar nucleosynthesis.

The 63Ni(n,γ) cross section has been measured for the first time at the neutron time-of-flight facility n_TOF at CERN from thermal neutron energies up to 200 keV. In total, capture kernels of 12 (new) resonances were determined. Maxwellian averaged cross sections were calculated for thermal energies from   kT=5-100  keV with uncertainties around 20%. Stellar model calculations for a 25M⊙ star show that the new data have a significant effect on the s-process production of 63Cu, 64Ni, and 64Zn in massive stars, allowing stronger constraints on the Cu yields from explosive nucleosynthesis in the subsequent supernova.

GEANT4 simulation of the neutron background of the C6D6 set-up for capture studies at n_TOF

The neutron sensitivity of the C6D6 detector setup used at n TOF for capture measurements has been studied by means of detailed GEANT4 simulations. A realistic software replica of the entire n TOF experimental hall, including the neutron beam line, sample, detector supports and the walls of the experimental area has been implemented in the simulations. The simulations have been analyzed in the same manner as experimental data, in particular by applying the Pulse Height Weighting Technique. The simulations have been validated against a measurement of the neutron background performed with a nat C sample, showing an excellent agreement above 1 keV. At lower energies, an additional component in the measured nat C yield has been discovered, which prevents the use of nat C data for neutron background estimates at neutron energies below a few hundred eV. The origin and time structure of the neutron background have been derived from the simulations. Examples of the neutron background for two di erent samples are demonstrating the important role of accurate simulations of the neutron background in capture cross section measurements.

Nuclear Structure TowardsN=40Ca60: In-Beamγ-Ray Spectroscopy ofTi58,60

Excited states in the neutron-rich N = 38, 36 nuclei (60)Ti and (58)Ti were populated in nucleon-removal reactions from (61)V projectiles at 90 MeV/nucleon. The γ-ray transitions from such states in these Ti isotopes were detected with the advanced γ-ray tracking array GRETINA and were corrected event by event for large Doppler shifts (v/c ∼ 0.4) using the γ-ray interaction points deduced from online signal decomposition. The new data indicate that a steep decrease in quadrupole collectivity occurs when moving from neutron-rich N = 36, 38 Fe and Cr toward the Ti and Ca isotones. In fact, (58,60)Ti provide some of the most neutron-rich benchmarks accessible today for calculations attempting to determine the structure of the potentially doubly magic nucleus (60)Ca.

Catheter stability in transradial coronary angiography: The one-catheter-concept and the impact of performance level in 1,419 patients

a Department of Cardiology, Angiology and Critical Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Christian-Albrechts-Universität Kiel, Germany b Department of Cardiology, Main-Taunus-Kliniken, Academic Hospital of the Johann-Wolfgang-Goethe Universität Frankfurt in Bad Soden, Germany c Department of Cardiology and Critical Care Medicine, Johannes-Wesling-Klinikum Minden, Academic Hospital of the Medical School Hannover, Minden, Germany

Neutron-skin thickness from the study of the anti-analog giant dipole resonance

The γ-decay of the anti-analog of the giant dipole resonance (AGDR) to the isobaric analog state has been measured following the p( 124Sn,n) reaction at a beam energy of 600 MeV/nucleon. The energy of the transition was also calculated with state-of-the-art self-consistent relativistic random-phase approximation (RPA) and turned out to be very sensitive to the neutronskin thickness (ΔRpn). By comparing the theoretical results with the measured one, the ΔRpn value for 124Sn was deduced to be 0.21 ± 0.07 fm, which agrees well with the previous results. The present method offers new possibilities for measuring the neutron-skin thicknesses of very exotic isotopes.

Time-of-flight mass measurements of neutron-rich chromium isotopes up to N = 40 and implications for the accreted neutron star crust

We present the mass excesses of 59-64Cr, obtained from recent time-of-flight nuclear mass measurements at the National Superconducting Cyclotron Laboratory at Michigan State University. The mass of 64Cr is determined for the first time, with an atomic mass excess of -33.48(44) MeV. We find a significantly different two-neutron separation energy S2n trend for neutron-rich isotopes of chromium, removing the previously observed enhancement in binding at N=38. Additionally, we extend the S2n trend for chromium to N=40, revealing behavior consistent with the previously identified island of inversion in this region. We compare our results to state-of-the-art shell-model calculations performed with a modified Lenzi-Nowacki-Poves-Sieja interaction in the fp shell, including the g9/2 and d5/2 orbits for the neutron valence space. We employ our result for the mass of 64Cr in accreted neutron star crust network calculations and find a reduction in the strength and depth of electron-capture heating from the A=64 isobaric chain, resulting in a cooler than expected accreted neutron star crust. This reduced heating is found to be due to the >1-MeV reduction in binding for 64Cr with respect to values from commonly used global mass models.

Transradial Coronary Angiography--Insights to the One-Catheter Concept.

Transradial coronary angiography (TRC) can be performed applying only one catheter fitting into the right and left coronary ostia (R/LCO). In this bicentric study (n = 2953), we analyzed the ostial performance of the Tiger_II_catheter widely used in TRC. Compared to Judkins catheters, the Tiger_II is frequently associated with ostial instability within the LCO but fits better into the RCO-irrespective of tube size. Judkins catheters generally need more peri-procedural contrast and radiation exposure. TRC may be started using a 5F_Tiger_II on the right side in order to be switched to 5F Judkins in case of propable LCO instability.

Treatment of isomers in nucleosynthesis codes

The decay properties of long-lived excited states (isomers) can have a significant impact on the destruction channels of isotopes under stellar conditions. In sufficiently hot environments, the population of isomers can be altered via thermal excitation or de-excitation. If the corresponding lifetimes are of the same order of magnitude as the typical time scales of the environment, the isomers have to be the treated explicitly. We present a general approach to the treatment of isomers in stellar nucleosynthesis codes and discuss a few illustrative examples. The corresponding code is available online at this http URL

Study of the spallation of136Xe in collision with1H and12C at 1 GeV per nucleon

The collision of 136Xe with a proton and with 12C at 1?GeV per nucleon has been studied in inverse kinematics with the SPALADIN setup at GSI. The detection in coincidence of the final state fragments (projectile residues, neutrons and Z???2 charged fragments) with a large geometrical efficiency is provided by the inverse kinematics combined with a large-aperture dipole magnet and large detectors. Such a coincidence, measured on an event basis, allows us to select the excitation energy of the prefragment formed after the nuclear cascade and study its different de-excitation channels such as evaporation of light particles, asymmetric binary decay or multifragmentation. After a short summary of spallation reactions modeling, followed by the description of the setup, some preliminary results will be shown including the cross-sections of the reaction on the proton, compared in particular to other measurements as well as the cross-sections for the various fragment multiplicities. In the last section, we explain our method for the selection of the prefragment excitation energy and give a hint of the variables available in our experiment to study the excitation energy dependence of the prefragment de-excitation mechanism for both reactions.

Neutron-induced cross sections: From raw data to astrophysical rates

Abstract.Neutron capture cross sections are one of the most important nuclear inputs to models of stellar nucleosynthesis of the elements heavier than iron. The activation technique and the time-of-flight method are mostly used to determine the required data experimentally. Recent developments of experimental techniques allow for new experiments on radioactive isotopes. Monte Carlo based analysis methods give new insights into the systematic uncertainties of previous measurements. We present an overview over the state-of-the-art experimental techniques, a detailed new evaluation of the 197Au(n,