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With the R$^{3}$B-LAND setup at GSI we have measured exclusive relative-energy spectra of the Coulomb dissociation of $^{18}$C at a projectile energy around 425~AMeV on a lead target, which are needed to determine the radiative neutron-capture cross sections of $^{17}$C into the ground state of $^{18}$C. Those data have been used to constrain theoretical calculations for transitions populating excited states in $^{18}$C. This allowed to derive the astrophysical cross section $\sigma^{*}_{\mathrm{n}\gamma}$ accounting for the thermal population of $^{17}$C target states in astrophysical scenarios. The experimentally verified capture rate is significantly lower than those of previously obtained Hauser-Feshbach estimations at temperatures $T_{9}\leq{}1$~GK. Network simulations with updated neutron-capture rates and hydrodynamics according to the neutrino-driven wind model as well as the neutron-star merger scenario reveal no pronounced influence of neutron capture of $^{17}$C on the production of second- and third-peak elements in contrast to earlier sensitivity studies.

International audience; Neutron-rich light nuclei and their reactions play an important role for the creation of chemical elements. Here, data from a Coulomb dissociation experiment on $^{20,21}$N are reported. Relativistic $^{20,21}$N ions impinged on a lead target and the Coulomb dissociation cross section was determined in a kinematically complete experiment. Using the detailed balance theorem, the $^{19}\mathrm{N}(\mathrm{n},\gamma)^{20}\mathrm{N}$ and $^{20}\mathrm{N}(\mathrm{n},\gamma)^{21}\mathrm{N}$ excitation functions and thermonuclear reaction rates have been determined. The $^{19}\mathrm{N}(\mathrm{n},\gamma)^{20}\mathrm{N}$ rate is up to a factor of 5 higher at $T

Coulomb breakup at high energy in inverse kinematics of proton-rich Cl-31 was used to constrain the thermonuclear S-30(p,gamma)Cl-31 capture reaction rate under typical Type I x-ray burst conditions. This reaction is a bottleneck during rapid proton-capture nucleosynthesis (rp process), where its rate depends predominantly on the nuclear structure of Cl-31. Two low-lying states just above the proton-separation threshold of S-p = 296( 50) keV in Cl-31 have been identified experimentally using the (RB)-B-3-LAND setup at the GSI Helmholtzzentrum fur Schwerionenforschung GmbH. Both states are considered to play a key role in the thermonuclear S-30( p,gamma)Cl-31 capture reaction. Excitation energies of the first J(pi) = 1/2(+), 5/2(+) states have been extracted and the reaction rate for proton capture on S-30 under typical rp-process temperatures has been investigated.

Radioactive beams of 14,15B produced by fragmentation of a primary 40Ar beam were directed onto a Pb target to investigate the neutron breakup within the Coulomb field. The experiment was performed at the LAND/R3B setup. Preliminary results for the Coulomb dissociation cross sections as well as for the astrophysically interesting inverse reactions, 13,14B(n,γ), are presented. © 2014 Elsevier Inc., This project was supported by the Helmholtz International Center for FAIR, the Helmholtz Young Investigator Group VH-NG-327 and the Helmholtz Alliance Program of the Helmholtz Association, Contract No. HA216/EMMI.

The very neutron-rich oxygen isotopes O-25 and O-26 are investigated experimentally and theoretically. The unbound states are populated in an experiment performed at the R3B-LAND setup at GSI via proton-knockout reactions from F-26 and F-27 at relativistic energies around 442 and 414 MeV/nucleon, respectively. From the kinematically complete measurement of the decay into O-24 plus one or two neutrons, the O-25 ground-state energy and width are determined, and upper limits for the O-26 ground-state energy and lifetime are extracted. In addition, the results provide indications for an excited state in O-26 at around 4 MeV. The experimental findings are compared to theoretical shell-model calculations based on chiral two- and three-nucleon (3N) forces, including for the first time residual 3N forces, which are shown to be amplified as valence neutrons are added.

5 pags., 3 figs., 1 tab. -- 11th Symposium on Nuclei in the Cosmos, 19-23 July 2010, Heidelberg, Germany, A Coulomb dissociation experiment on the proton-rich 32Ar and 34Ar isotopes was performed at the ALADIN-LAND setup at GSI in Darmstadt. Recent RQRPA calculations show a low-lying E1 soft-vibrational mode at an excitation energy Ex ≈ 9 MeV for proton-rich argon isotopes at the dripline. In a macroscopic picture, this can be understood as an out-of-phase oscillation of a thin proton skin against the isospin-saturated core, similar to the neutron pygmy resonance at the neutron dripline. On the other hand, the measured (γ, p) reactions are interesting for the calculation of reaction cross-sections and radiative proton capture rates for the rp-process. In this hydrogen burning process a lot of nuclear structure inputs are still missing. Especially in the argon region a bottleneck for the reaction flow is assumed at 30S and 34Ar. The impact of the predicted proton pygmy resonance on the reaction flow is not yet clear. The experimental motivation and the experiment itself are described. Identification plots for incoming and outgoing particles are shown and a tracking algorithm is applied and shows to work succesfully., This project is supported by the HGF Young Investigators Project VH-NG-327.

Reduced uncertainty in the thermonuclear rate of the {sup 33}S(p,{gamma}){sup 34}Cl reaction would help to improve our understanding of nucleosynthesis in classical nova explosions. At present, models are generally in concordance with observations that nuclei up to roughly the calcium region may be produced in these explosive phenomena; better knowledge of this rate would help with the quantitative interpretation of nova observations over the S-Ca mass region, and contribute towards the firm establishment of a nucleosynthetic endpoint. As well, models find that the ejecta of nova explosions on massive oxygen-neon white dwarfs may contain as much as 150 times the solar abundance of {sup 33}S. This characteristic isotopic signature of a nova explosion could possibly be observed through the analysis of microscopic grains formed in the environment surrounding a nova and later embedded within primitive meteorites. An improved {sup 33}S(p,{gamma}){sup 34}Cl rate (the principal destruction mechanism for {sup 33}S in novae) would help to ensure a robust model prediction for the amount of {sup 33}S that may be produced. Finally, constraining this rate could confirm or rule out the decay of an isomeric state of {sup 34}Cl(E{sub x} = 146 keV, t{sub 1/2} = 32 m) as a source formore » observable gamma-rays from novae. We have performed several complementary experiments dedicated to improving our knowledge of the {sup 33}S(p,{gamma}){sup 34}Cl rate, using both indirect methods (measurement of the {sup 34}S({sup 3}He,t){sup 34}Cl and {sup 33}S({sup 3}He,d){sup 34}Cl reactions with the Munich Q3D spectrograph) and direct methods (in normal kinematics at CENPA, University of Washington, and in inverse kinematics with the DRAGON recoil mass separator at TRIUMF). Our results will be used with nova models to facilitate comparisons of model predictions with present and future nova observables.« less

The radiative proton-capture reactions {sup 19}Ne(p,{gamma}){sup 20}Na, {sup 23}Mg(p,{gamma}){sup 24}Al, {sup 27}Si(p,{gamma}){sup 28}P, {sup 31}S(p,{gamma}){sup 32}Cl, and {sup 35}Ar(p,{gamma}){sup 36}K potentially influence energy generation and/or nucleosynthesis during explosive hydrogen burning in classical novae and/or type I x-ray bursts. The thermonuclear rates of these reactions are dependent on resonance energies E{sub r}=E{sub x}-Q and strengths {omega}{gamma}. The {sup 20}Ne({sup 3}He,t){sup 20}Na, {sup 24}Mg({sup 3}He,t){sup 24}Al, {sup 28}Si({sup 3}He,t){sup 28}P, {sup 32}S({sup 3}He,t){sup 32}Cl, and {sup 36}Ar({sup 3}He,t){sup 36}K reactions have been measured using a 32-MeV, {sup 3}He{sup 2+} beam; ion-implanted carbon-foil targets developed at the University of Washington; and the Munich Q3D magnetic spectrograph. This experiment has already yielded precision mass measurements of {sup 20}Na, {sup 24}Al, {sup 28}P, and {sup 32}Cl [C. Wrede et al., Phys. Rev. C 81, 055503 (2010)], which are used presently to constrain the corresponding (p,{gamma}) reaction Q values. The new {sup 24}Al and {sup 28}P masses resolve a discrepancy in the energy of the lowest-energy resonance in the {sup 23}Mg(p,{gamma}){sup 24}Al reaction and better constrain a direct measurement of its strength. Excitation energies in {sup 32}Cl and {sup 36}K have also been measured. An important new proton-unbound level has been found at E{sub x}=2196.9(7) keVmore » in {sup 36}K and the uncertainties in {sup 36}K excitation energies have been reduced by over an order of magnitude. Using the new data on {sup 36}K, the A=36, T=1 triplets have been reassigned. The thermonuclear {sup 35}Ar(p,{gamma}){sup 36}K reaction rate is found to be much higher than a commonly adopted rate and this could affect energy generation in type I x-ray bursts.« less

With the Q3D magnetic spectrograph of the Maier-Leibnitz-Laboratorium at M\"unchen at a resolution of about 3 keV, angular distributions and excitation functions of the reaction $^{208}\mathrm{Pb}$($p,{p}^{\ensuremath{'}}$) were measured at some scattering angles ${20}^{\ifmmode^\circ\else\textdegree\fi{}}$--${138}^{\ifmmode^\circ\else\textdegree\fi{}}$ for several proton energies $14.8$--$18.1$ MeV. All seven known isobaric analog resonances in $^{209}\mathrm{Bi}$ are covered. By the excitation near the $j{}_{15/2}$ intruder resonance in $^{209}\mathrm{Bi}$, several new positive parity states in $^{208}\mathrm{Pb}$ with excitation energies $4.6$--$6.2$ MeV are identified by comparison of the mean cross section to the known single particle widths. The dominant configuration for 27 positive parity states is determined and compared to the schematic shell model.

High-precision measurements of superallowed ${0}^{+}\ensuremath{\rightarrow}{0}^{+}$ $\ensuremath{\beta}$ decays of $T=2$ nuclides such as $^{20}\mathrm{Mg}$, $^{24}\mathrm{Si}$, $^{28}\mathrm{S}$, and $^{32}\mathrm{Ar}$ can contribute to searches for physics beyond the standard model of particle physics if the ${Q}_{\mathrm{EC}}$ values are accurate to a few keV or better. As a step toward providing precise ${Q}_{\mathrm{EC}}$ values for these decays, the ground-state masses of the respective daughter nuclei $^{20}\mathrm{Na}$, $^{24}\mathrm{Al}$, $^{28}\mathrm{P}$, and $^{32}\mathrm{Cl}$ have been determined by measuring the ($^{3}\mathrm{He},t$) reactions leading to them with the $^{36}\mathrm{Ar}$($^{3}\mathrm{He},t$)$^{36}\mathrm{K}$ reaction as a calibration. A quadrupole-dipole-dipole-dipole (Q3D) magnetic spectrograph was used together with thin ion-implanted carbon-foil targets of $^{20}\mathrm{Ne}$, $^{24}\mathrm{Mg}$, $^{28}\mathrm{Si}$, $^{32}\mathrm{S}$, and $^{36}\mathrm{Ar}$. The masses of $^{20}\mathrm{Na}$ and $^{32}\mathrm{Cl}$ are found to be in good agreement with the values from the 2003 Atomic Mass Evaluation (AME03) [G. Audi, A. H. Wapstra, and C. Thibault, Nucl. Phys. A 729, 337 (2003)], and the precision has been improved by a factor of 6 in both cases. The masses of $^{24}\mathrm{Al}$ and $^{28}\mathrm{P}$ are found to be higher than the values from AME03 by 9.5 keV ($3.2\ensuremath{\sigma}$) and 11.5 keV ($3.6\ensuremath{\sigma}$), respectively, and the precision has been improved by a factor of 2.5 in both cases. The new $^{32}\mathrm{Cl}$ mass is used together with the excitation energy of its lowest $T=2$ level and the mass of $^{32}\mathrm{Ar}$ to derive an improved superallowed ${Q}_{\mathrm{EC}}$ value of 6087.3(22) keV for this case. The effects on quantities related to standard-model tests including the $\ensuremath{\beta}$-$\ensuremath{\nu}$ correlation coefficient $a$ and the isospin-symmetry-breaking correction ${\ensuremath{\delta}}_{C}$ are examined for the $A=32$ case.

WOS: 000270326800009, The construction and properties of three sets of two-dimensional scintillating fiber detector arrays for tracking of charged particles used in the HypHI Phase 0 experiment at GSI will be reported in this paper. The position resolutions and the detection efficiency of detectors have been obtained for each layer of detectors by using Li-6 primary beams and particles with Z = 1 produced by fragment reactions of Xe-136 projectiles on the hydrogen target. Besides, the response of energy deposition of charged particles in the first detector set placed right behind the target has been studied by using light projectile fragments with Z = 1, 2 and 3 produced by Ni-58 and C-12 beams. Extracted resolutions for energy deposition and position as well as the detection efficiency fulfill the requirements of the HypHl Phase 0 experiment. (C) 2009 Elsevier B.V. All rights reserved., Helmholtz association as Helmholtz-University Young Investigators Group [VH-NG-239]; German Research Foundation (DFG) [SA 1696/1-1]; Ministry of Education, Science and Culture of Japan [18042008]; EU FP7 HadronPhysic2 SPHERE, We would like to thank the accelerator department at GSI for providing us beams with excellent conditions. We would also thank H. lwase, R. Pleskac and D. Schardt to help us during the experiment in cave A at GSI. We would like to show our appreciation to the FOPI and SPALADIN collaboration to provide us beams behind their experimental setups. We would also like to show our gratitude to the Detector Laboratory at GSI, Electronics Department of the Institute for Nuclear Physics of Mainz University, the Experimental Electronics Department at GSI and the Target Laboratory at GSI for their supports for the development. The HypHI project is funded by the Helmholtz association as Helmholtz-University Young Investigators Group VH-NG-239 at GSI, and German Research Foundation (DFG) with a contract number SA 1696/1-1. The authors acknowledge financial support by the Ministry of Education, Science and Culture of Japan, Grantin-Aid for Scientific Research on Priority Areas 449. This work is also supported by the Ministry of Education, Science and Culture of Japan, Grant-in-Aids for Scientific Research 18042008 and EU FP7 HadronPhysic2 SPHERE.

Even though both experimental and theoretical activities on hypernuclear physics have been extended by a number of international projects, direct measurements on hypernuclear magnetic moments and studies of hypernuclei at extreme isospins have never been performed. The international HypHI collaboration proposes to perform hypernuclear spectroscopy with stable heavy ion beams and rare isotope beams at GSI and FAIR in order to study neutron and proton rich hypernuclei and to measure directly hypernuclear magnetic moments. The project is divided into four phases. In the first Phase 0 experiment, the feasibility of precise hypernuclear spectroscopy with heavy ion beams will be demonstrated by observing π − decay channels of Λ 3 H, Λ 4 H and Λ 5 He with 6Li projectiles at 2 A GeV impinging on a 12C target. In the later Phases 1 through 3, studies of proton and neutron rich hypernuclei, direct measurements of hypernuclear magnetic moments and the spectroscopy of hypernuclei toward the nucleon drip-lines are planned.