Search

The production cross sections of neutron-rich fission residues in reactions induced by U238 projectiles at 950A MeV impinging on Pb and Be targets are investigated at the Fragment Separator at GSI. These two targets allow us to investigate fission processes induced by two reaction mechanisms, Coulomb and nuclear excitations, and to study the role of these mechanisms in the neutron excess of the final fragments. © 2019 American Physical Society.

International audience; Neutron- and proton-removal cross sections for nuclei around ^132Sn have been systematically measured. The measurements clearly show the effect of the N = 82 closed shells. Model calculations describing all processes leading to single nucleon removal residual nuclei provide a reasonable description of the neutron removal process but clearly overestimate the proton removal ones. This overestimation of the proton removal channels could be explained as due to the presence of short-range correlated neutron-proton pairs in nuclei.

Single-neutron and single-proton removal cross sections have been measured for medium-mass neutron-rich nuclei around Z=50 and energies around 1000A MeV using the FRagment Separator (FRS) at GSI. The measured cross sections confirm the relative low values of the proton-removal cross sections, observed since a long time ago and not yet understood. Model calculations considering the knock-out process together with initial- and final-state interactions describe the measured neutron-removal cross sections. Proton-removal cross sections are, however, significantly over-predicted by the same calculations. The observed difference can be explained to a large extent by the knock-out of short-range correlated nucleons from dominant neutron-proton pairs in neutron-rich nuclei.

8 pags., 10 figs., 3 tabs., The Borromean drip-line nucleus Ne-17 has been suggested to possess a two-proton halo structure in its ground state. In the astrophysical rp-process, where the two-proton capture reaction O-15(2p,gamma) Ne-17 plays an important role, the calculated reaction rate differs by several orders of magnitude between different theoretical approaches. To add to the understanding of the Ne-17 structure we have studied nuclear and electromagnetic dissociation. A 500 MeV/u Ne-17 beam was directed toward lead, carbon, and polyethylene targets. Oxygen isotopes in the final state were measured in coincidence with one or two protons. Different reaction branches in the dissociation of Ne-17 were disentangled. The relative populations of s and d states in F-16 were determined for light and heavy targets. The differential cross section for electromagnetic dissociation (EMD) shows a continuous internal energy spectrum in the three-body system O-15 + 2p. The Ne-17 EMD data were compared to current theoretical models. None of them, however, yields satisfactory agreement with the experimental data presented here. These new data may facilitate future development of adequate models for description of the fragmentation process., This project is supported by NAVI, GSI-TU Darmstadt cooperation, HIC for FAIR, EMMI, and BMBF and from DFG through Grant No. SFB1245 and from BMBF via Project No. 05P15RDFN1, and from the Spanish Ministry by research grant FPA2015-64969-P. C.A.B. acknowledges support by the US DOE Grant No. DE-FG02-08ER41533 and the US NSF Grant No. 1415656.

Open Access funded by SCOAP3 - Sponsoring Consortium for Open Access Publishing in Particle Physics, One-neutron knockout reactions from Borromean nuclei are analyzed using a profile function analysis technique. The profile function, which is derived as the square root of the variance of the measured fragment + neutron momenta as a function of their relative energy, is shown to be very sensitive to the angular momentum of the knocked out neutron. Three cases are studied here: 7He, where the profile function analysis shows a presence of (s1/2)2 component in the 8He ground-state wave-function, 10Li, where the presence of a 11(2)% d-wave contribution to the relative energy spectrum above 1.5 MeV is found and, finally, the presence of a major s contribution around 0.5 MeV relative energy in the 13Be case and that the observed decay to the 12Be 2+ state originates in a d state in 13Be. © 2012 Elsevier Open access under CC BY license., Financial support from the Swedish Research Council and the Spanish Ministry through the research grant FPA2009-07387 is also acknowledged.

J. Marganiec et al. ; 15 págs.; 14 figs.; 6 tabs., The proton-capture reaction Si26(p,γ)P27 was studied via Coulomb dissociation (CD) of P27 at an incident energy of about 500 MeV/u. The three lowest-lying resonances in P27 have been populated and their resonance strengths have been measured. In addition, a nonresonant direct-capture component was clearly identified and its astrophysical S factor measured. The experimental results are compared to Monte Carlo simulations of the CD process using a semiclassical model. Our thermonuclear reaction rates show good agreement with the rates from a recent compilation. With respect to the nuclear structure of P27 we have found evidence for a negative-parity intruder state at 2.88-MeV excitation energy. ©2016 American Physical Society, This project was supported by BMBF, EU(EURONS), EMMI, GSI Darmstadt, FIAS, NAVI, GSI-TU Darmstadt cooperation, and HIC for FAIR. S.T. was supported by the Helmholtz Association (HGF) through the Nuclear Astrophysics Virtual Institute (VH-VI-417). C.L. acknowledges support from JINA-CEE under Grants No. PHY-1430152 and No. PHY-0822648 of the National Science Foundation. S.B.N. and the University of Santiago de Compostela group acknowledge support from the Spanish Ministerio de Educacion, under Grants No. FPU-AP2006-01474, No. FPA2012-39404-C02- 01, and No. FPA2013-47831-C2-1 and from Xunta de Galicia under Grant No. GRC2013-11.

R. Reifarth et al: ; 12 págs.; 9 figs.; Open Access funded by Creative Commons Atribution Licence 3.0 ; Nuclear Physics in Astrophysics VI (NPA6), The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process ow and r-process -decay chains. These nuclei are attributed to the p and rp process. For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections. The Facility for Antiproton and Ion Research (FAIR) will oer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes., This project was supported by the HGF Young Investigators Project VH-NG-327, EMMI, H4F, HGS-HIRe, JINA, NAVI, DFG and ATHENA.

We present experimental results on the electromagnetic excitation of neutron-rich nickel isotopes, making use of the (RB)-B-3-LAND setup at GSI. Exotic beams were produced at approximately 500 MeV/u and their reactions were studied in inverse kinematics. Integral cross sections for Ni-58 are discussed and compared to previous data, providing a validation of our experimental method. The El excitation-energy distribution of the unstable Ni-68 is presented as well, showing an excess in cross section in the 1n decay channel when compared only with a typical Giant Dipole Resonance.

The fragmentation of neutron-rich Sn 132 nuclei produced in the fission of U 238 projectiles at 950 A MeV has been investigated at the FRagment Separator (FRS) at GSI. This work represents the first investigation of fragmentation of medium-mass radioactive projectiles with a large neutron excess. The measured production cross sections of the residual nuclei are relevant for the possible use of a two-stage reaction scheme (fission + fragmentation) for the production of extremely neutron-rich medium-mass nuclei in future rare-ion-beam facilities. Moreover, the new data will provide a better understanding of the “memory” effect in fragmentation reactions.

We report on a new experimental setup for the investigation of proton induced reactions on exotic nuclei in inverse kinematics. It was installed and successfully used in the scattering study of intermediate-energy protons ( ∼ 700 MeV / u ) on neutron-rich nuclei 6,8He produced with the FRagment Separator (FRS) at the GSI facility, Darmstadt. A new pure liquid-hydrogen target was successfully adapted allowing to obtain low-background data as compared to commonly used (CH2)n targets. Absolute differential cross-sections for elastic (p,6,8He) scattering were obtained at angles corresponding to 0.05 ⩽ | t | ⩽ 0.125 (GeV/c)2 of the four-momentum transfer squared (−t) leading to the first diffraction minimum and spanning more than two orders of magnitude. They complement an earlier measurement at smaller angles 0.0025 ⩽ | t | ⩽ 0.05 (GeV/c)2 performed at the same energy with an active target. Both data sets agree well in the overlap region t ≈ 0.05 (GeV/c)2 and enable a refined and comparative study of the radial distribution of the nuclear matter density.

The recently claimed observations of non-negligible amounts of 6Li in old halo stars have renewed interest in the big bang nucleosynthesis (BBN) of 6Li. One important ingredient in the predicted BBN abundance of 6Li is the low-energy 2 H ( α , γ ) 6 Li cross section. Up to now, the only available experimental result for this cross section showed an almost constant astrophysical S -factor below 400 keV, contrary to theoretical expectations. We report on a new measurement of the 2 H ( α , γ ) 6 Li reaction using the break-up of 6Li at 150 A MeV. We find clear evidence for Coulomb-nuclear interference by analyzing the scattering-angular distributions. This is in-line with our theoretical description which indicates a drop of the S 24 -factor at low energies as predicted also by most other models. Consequently, we find even lower upper limits for the calculated primordial 6Li abundance than before.

The Super-FRS is designed as a versatile partially superconducting fragment separator for the planned international Facility for Antiprotons and Ion Research. It will be able to separate all kinds of nuclear projectile fragments of primary heavy-ion beams including uranium with energies of up to 1.5 GeV/u and intensities of up to 10 12 particles/s. The primary beam power of up to 50 kW has to be dumped in six shaped beam catchers in accordance with the ion optical setting of the separator in order not to enter the main separator, which will have accordingly weaker shielding. A key issue for such a high-power facility is the activation of several components and thus their access by maintenance personnel. Both the prompt and the residual dose due to activation are calculated by means of the Monte Carlo particle transport code FLUKA. The biological shielding in the target area will be realized by massive iron blocks (thickness ≈ 2 m) around the beam tube and the magnets. This will be surrounded by up to 6 m of concrete in order to reduce the dose rates below the design value of 0.5 μSv/h, which is in agreement with the German radiation protection ordinance for public access. A dedicated maintenance channel is foreseen in which the residual dose rates are tolerable for short time access after a certain cooling time.

The fragment separator Super-FRS is an important part of the planned international facility for antiproton and ion research (FAIR). The high intensity heavy ion beams with a beam power of up to 40 kW for uranium require strong shielding of the area and safe handling of the components in the beamline. As the primary beam may be dumped at many positions along the separator the whole first part of the Super-FRS will be located in a dedicated target hall. The layout of this target hall is presented in this paper. The combination of iron and concrete for the biological shielding is determined by dose rate calculations with a radiation transport code (FLUKA) which can also treat heavy ions and predict dose rates after activation. The resulting layout foresees a compact iron shielding surrounded by many meters of concrete shielding. A plug system is used to insert devices into the beamline. A crane can transport these plugs to a nearby hot cell. The thickness of the inner shielding was adjusted to reduce the calculated dose rate on a working platform after a short waiting time to enable hands-on maintenance. Very important for the handling concept is the predicted activation of the devices inserted into the beam and of the shielding material itself.

The unbound isotopes 10Li, 12Li and 13Li have been observed after nucleon-knockout reactions at relativistic energies with 11Li and 14Be beams impinging on a liquid hydrogen target. The channels , and were analysed in the ALADIN-LAND setup at GSI. The 10Li data confirm earlier findings, while the 12Li and 13Li nuclei were observed for the first time. The relative-energy spectrum shows that the ground state of 12Li can be described as a virtual s-state with a scattering length of -13.7(1.6) fm. A broad energy spectrum was found for the channel. Based on the assumption that the relative-energy spectrum is dominated by a correlated background presumably stemming from initial correlations in the 14Be ground-state, evidence for a 13Li resonance at 1.47(31) MeV above the threshold with a width around 2 MeV has been found.

The integrity of the liquid lithium jet after pulsed ion beam irradiation is investigated by means of three-dimensional hydrodynamic simulations combined with an analytical analysis of the target response. It is predicted that for the desired beam intensity the heated target will be destroyed due to spallation and following fragmentation of the heated matter. The stability of the liquid lithium jet after ion beam heating is a crucial question for design of the fragment separator Super-FRS, which will be a part of the new FAIR facility at GSI.

The interaction cross-sections of neutron-deficient Kr-72,Kr-76,Kr-80 isotopes have been measured by use of the transmission method at relativistic energies. Based on the Glauber model analysis effective root-mean-square matter radii of these nuclei have been determined for the first time. A systematic evolution of the matter radii in the mass A similar to 70 region is discussed and compared with that of light nuclei., The original publication is available at www.epj.org.

The neutron-rich isotopes 129–133Sn were studied in a Coulomb excitation experiment at about 500 AMeV using the FRS-LAND setup at GSI. From the exclusive measurement of all projectile-like particles following the excitation and decay of the projectile in a high-Z target, the energy differential cross section can be extracted. At these beam energies dipole transitions are dominating, and within the semi-classical approach the Coulomb excitation cross sections can be transformed into photoabsorption cross sections. In contrast to stable Sn nuclei, a substantial fraction of dipole strength is observed at energies below the giant dipole resonance (GDR). For 130Sn and 132Sn this strength is located in a peak-like structure around 10 MeV excitation energy and exhibits a few percent of the Thomas-Reiche Kuhn (TRK) sum-rule strength. Several calculations predict the appearance of dipole strength at low excitation energies in neutron-rich nuclei. This low-lying strength is often referred to as pygmy dipole resonance (PDR) and, in a macroscopic picture, is discussed in terms of a collective oscillation of excess neutrons versus the core nucleons. Moreover, a sharp rise is observed at the neutron separation threshold around 5 MeV for the odd isotopes. A possible contribution of 'threshold strength', which can be described within the direct-breakup model is discussed. The results for the neutron-rich Sn isotopes are confronted with results on stable nuclei investigated in experiments using real photons.

Interaction cross–sections of 72,76,80 Kr on a C target were measured at the projectile fragment separator FRS at GSI. We deduced the effective matter radii of the nuclei by a Glauber model analysis. An increase of matter radii toward the proton drip–line was observed.

A systematic study of isotopic effects in the break-up of projectile spectators at relativistic energies has been performed with the ALADiN spectrometer at the GSI laboratory. Searching for signals of criticality in the fragment production we have applied the model independent universal fluctuations theory already proposed to track criticality signals in multifragmentation to our data. The fluctuation of the largest fragment charge and of the asymmetry of the two and three largest fragments and their bimodal distribution have also been analysed., Comment: 6 pages, 4 figures, IX International Conference on Nucleus-Nucleus Collisions, Rio de Janeiro, Brazil, August 28 - September 1, 2006

This work presents a direct measurement of the $^{96}$Ru($p, \gamma$)$^{97}$Rh cross section via a novel technique using a storage ring, which opens opportunities for reaction measurements on unstable nuclei. A proof-of-principle experiment was performed at the storage ring ESR at GSI in Darmstadt, where circulating $^{96}$Ru ions interacted repeatedly with a hydrogen target. The $^{96}$Ru($p, \gamma$)$^{97}$Rh cross section between 9 and 11 MeV has been determined using two independent normalization methods. As key ingredients in Hauser-Feshbach calculations, the $\gamma$-ray strength function as well as the level density model can be pinned down with the measured ($p, \gamma$) cross section. Furthermore, the proton optical potential can be optimized after the uncertainties from the $\gamma$-ray strength function and the level density have been removed. As a result, a constrained $^{96}$Ru($p, \gamma$)$^{97}$Rh reaction rate over a wide temperature range is recommended for $p$-process network calculations.

J. Marganiec et al.; 9 pags.; 11 figs.; 2 tabs., © 2015, SIF, Springer-Verlag Berlin Heidelberg. Two-proton decay of the unbound Tz = -2 nucleus 16Ne , produced in one-neutron knockout from a 500 MeV/u 17Ne beam, has been studied at GSI. The ground state, at a resonance energy 1.388(15) MeV, (Γ = 0.082(15) MeV) above the 14O +p+p threshold, and two narrow resonances at Er = 3.220(46) MeV and 7.57(6) MeV have been investigated. A comparison of the energy difference between the first excited 2+ state and the 0+ ground state in 16Ne with its mirror nucleus 16C reveals a small Thomas-Ehrman shift (TES) of +70(46) keV. A trend of the TES for the T = 2 quintet is obtained by completing the known data with a prediction for 16F obtained from an IMME analysis. The decay mechanisms of the observed three resonances were revealed from an analysis of the energy and angular correlations of the 14O +p+p decay products. The ground state decay can be considered as a genuine three-body (democratic) mode and the excited states decay sequentially via states in the intermediate nucleus 15F , the 3.22 MeV state predominantly via the 15F ground-state resonance, while the 7.57 MeV state decays via the 5/2+ resonance in 15F at 2.8 MeV above the 14O +p+p threshold. Further, from an analysis of angular correlations, the spin-parity of the 7.57 MeV state has been determined as IП = 2+ and assigned as the third 2+ state in 16Ne based on a comparison with 16C., This work is partly supported by the Helmholtz International Center for FAIR within the framework of the LOEWE program launched by the State of Hesse, by the German Federal Ministry for Education and Research (BMBF), EU(EURONS), ExtreMe Matter Institute EMMI, GSI-TU Darmstadt cooperation, Nuclear Astrophysics Virtual Institutes NAVI. Financial support from the Swedish Research Council, the Spanish grants FPA-2010-17142, MICCIN FPA2009-14604-C02-01, FPA2012- 39404-C02-01and MINECO FPA 2012-32443 are also acknowledged. One of us (BJ) is a Helmholtz International Fellow

The production cross-sections of proton-rich protactinium and thorium isotopes have been investigated for the fragmentation of 1 A GeV 238 U in a beryllium target at the SIS/FRS facility at GSI Darmstadt. The experimental results are compared with the predictions of an abrasion-ablation model of nuclear fragmentation yielding good overall agreement. Weak evidence for flrst observation of new isotopes 208 Th and 211 Pa is presented.

The population of metastable states produced in relativistic-energy fragmentation of a U-238 beam has been measured. For states with angular momentum greater than or similar to 20h, a much higher population than expected has been observed. By introducing a collective component to the generation of angular momentum the experimental data can be understood. This is the first time that a collective degree of freedom has be shown to play a major role in such high-energy collisions. (c) 2005 Elsevier B.V. All rights reserved.

Inelastic scattering of loosely bound nuclei by Coulomb interaction at intermediate energies (400?600 MeV/nucleon) has been utilized as a spectroscopic tool for exotic nuclei. The observed electromagnetic dipole (E1) strength above the one neutron threshold of neutron-rich C, Be, B and O isotopes can be explained by a non-resonant transition of a neutron into the continuum. The shape of these strength distributions reflects properties of the wavefunction of the released neutron in the nucleus and hence ground-state properties of these isotopes. Neutron capture cross-sections such as for the 14C(n,?) 15C reaction which are of astrophysical relevance can be deduced indirectly.

This paper presents the results of experimental investigations of ( p , p n ) , ( p , p α ) and ( p , p 6 He) reactions with relativistic 6 He and 8 He beams impinging on a hydrogen target. Information on the structure of extremely neutron-rich nuclei was obtained by using the unique characteristic of quasi-free scattering processes and inverse kinematics. For the first time, momentum distributions of complex clusters inside 6 He and 8 He were measured. Spectroscopic factors for valence neutrons, α - and 6 He clusters were deduced from the experimental data. They demonstrate that the filling of the p 1 2 shell is the essential feature of the 8 He structure. It is shown that the 8 He cluster structure can be considered as a 6 He core plus two valence neutrons.

The projectile fragmentation of a 92 Mo beam onto a beryllium target at an incident energy of 500 A MeV has been studied at the high-resolution spectrometer FRS at GSI. The isotopic production cross-sections of the projectile fragments produced in the reaction have been determined. The data have been compared to the empirical parameterisation, EPAX, and to a microscopic nuclear reaction model, ABRABLA.

Breakup reactions were used to study the ground-state configuration of the neutron-rich isotope 23O. The 22O fragments produced in one-nucleon removal from 23O at 938 MeV/nucleon in a carbon target were detected in coincidence with de-exciting γ rays, allowing to discern between 22O ground-state and excited-states contributions. From the comparison of exclusive experimental momentum distributions for the one-neutron removal channel to theoretical momentum distributions calculated in an Eikonal model for the knockout process, and spin and parity assignment of I π = 1/2+ was deduced for the 23O ground state. This result solved the existent experimental discrepancy.

A superconducting fragment separator (Super-FRS) is being designed for the production and separation of radioactive isotopes at the future FAIR (Facility for Antiprotons and Ion Research) facility at Darmstadt. This paper discusses various aspects and requirements for the high-power production target that will be used in the Super-FRS experiments. The production target must survive over an extended period of time as it will be used during the course of many experiments. The specific power deposited by the high intensity beam that will be generated at the future FAIR facility will be high enough to destroy the target in most of the cases as a result of a single shot from the new heavy ion synchrotrons SIS100/300. By using an appropriate beam intensity and focal spot parameters, the target would survive after being irradiated once. However, the heat should be dissipated efficiently before the same target area is irradiated again. We have considered a wheel shaped solid carbon target that rotates around its axis so that different areas of the target are irradiated successively. This allows for cooling of the beam heated region by thermal conduction before the same part of the target is irradiated a second time. Another attractive option is to use a liquid jet target at the Super-FRS. First calculations of a possible liquid lithium target are also presented in this paper. One of the advantages of using lithium as a target is that it will survive even if one uses a smaller focal spot, which has half the area of that used for a solid carbon target. This will significantly improve the isotope resolution.A similar problem associated with these experiments will be safe deposition of the beam energy in a beamdump after its interaction with the production target. We also present calculations to study the suitability of a proposed beamdump.

The Rare ISotopes INvestigation at GSI project combines the former EUROBALL Ge-Cluster detectors, the MINIBALL Ge detectors, BaF2--HECTOR detectors, and the fragment separator at GSI for high-resolution in-beam gamma-ray spectroscopy measurements with radioactive beams. These secondary beams produced at relativistic energies are used for Coulomb excitation or secondary fragmentation experiments in order to explore the nuclear structure of the projectiles or projectile like nuclei by measuring de-excitation photons. The newly designed detector array is described and the performance characteristics are given. Moreover, particularities of the experimental technique are discussed.

The ground-state structure of the near-drip-line nucleus 23O has been investigated in a one-neutron Coulomb breakup reaction. Differential cross sections d σ / d E * for electromagnetic excitation of 23O projectiles (422 MeV/nucleon) incident on a lead target have been obtained from the measurement of the momenta of all breakup products including γ rays. The analysis of the deduced dipole-transition probability into the continuum infers a 2 s 1 / 2 ⊗ O 22 ( 0 + ) ground state configuration with a spectroscopic factor of 0.77(10) and thus a ground-state spin I π ( O 23 ) = 1 / 2 + , resolving earlier conflicting experimental findings. Final-state interaction is of significant influence, an effective reduced scattering length for low-energy p 3 / 2 neutron scattering could be derived from the data.

4 pages, 4 figures.-- Printed version published Dec 27, 2004.-- Issue title: "Proceedings of the Sixth International Conference on Radioactive Nuclear Beams (RNB6)" (Argonne, Illinois, US, Sep 22-26, 2003)., One-nucleon removal reactions at relativistic energies have been used as a spectroscopic tool to characterise the ground state properties of several neutron-rich isotopes in the sd-shell. Using the FRS at GSI, the longitudinal momentum distributions of the emerging fragments after one-nucleon removal were measured. The relative contributions of the remaining fragments in their ground and excited states have been determined from measurements of γ rays in coincidence with the longitudinal momentum distributions. In particular the breakup of O-23 has been investigated. The interpretation of our measurements, in the framework of a simple theoretical model, favours a spin and parity assignment of 1/2+ for the O-23 ground state in agreement with shell model predictions.

We have measured production cross-sections and longitudinal momentum distributions of fragments from neutron-deficient 36 Ar at 1.05 A GeV. The production cross-sections show excellent agreement with the predictions of the semiempirical formula EPAX . We have compared these results, involving extremely neutron deficient nuclei, with model calculations to extract information about the response of these models close to the driplines. The longitudinal momentum distributions have also been extracted and are compared with the Goldhaber and Morrissey systematics.

One-proton removal reactions of 936 MeV/u 8 B have been studied with carbon and lead as breakup targets. Using the FRS at GSI, the longitudinal momentum distributions of the 7 Be fragments and the one-proton removal cross section of 8 B were measured. The relative contributions of the breakup channels leading to 7 Be in its ground state and excited state at 429 keV ( 7 Be ∗ ) have been determined from measurements of γ rays in coincidence with the fragments from the one-proton removal reaction. The experimental breakup data are discussed in the context of a theoretical ( α+ 3 He + p ) three-body model. The combined data from the two targets allow a determination of the weight of the 7 Be ∗ component in the 8 B ground state wave function as (13.3±2.2%)

The empirical parametrization of fragmentation cross sections, EPAX, has been successfully applied to estimate fragment production cross sections in reactions of heavy ions at high incident energies. It is checked whether a similar parametrization can be found for proton-induced spallation around 1 GeV, the range of interest for ISOL-type RIB facilities. The validity of EPAX for medium-energy heavy-ion induced reactions is also checked. Only a few datasets are available, but in general EPAX predicts the cross sections rather well, except for fragments close to the projectile, where the experimental cross sections are found to be larger.

The relative momentum spread of in-flight separated exotic nuclear beams produced in fragmentation and/or fission reactions is of the order of a few percent. A new technique is presented, which reduces the momentum spread significantly, and first experimental results obtained with relativistic projectile fragments are shown. This technique is the key to experiments with slowed-down and stopped beams, in particular for the efficient stopping of relativistic exotic nuclei in gas-filled stopping cells. It will be employed at the energy-buncher stage of the low-energy branch of the Super-FRS facility. The ion-optical design of the energy buncher is presented and a brief outlook to the experimental program is given.

The 7Be(p, γ)8B reaction has been studied at GSI via the Coulomb Dissociation of 8B at 254 A MeV, using the large acceptance spectrometer KAOS to detect the outgoing fragments. We have studied experimentally the E2 contribution to the Coulomb Dissociation by measuring the angular correlations of the breakup fragments. The resulting astrophysical S17 factor is compared to the results of other direct and indirect measurements.

GSI proposes to build a next-generation facility for research with relativistic beams of ions and antiprotons. This facility allows a broad range of topics in nuclear and astrophysics, plasma and atomic physics to be addressed. The topic most interesting in the context of this conference is physics with high-intensity beams of exotic nuclei. In addition, a short overview of the opportunities in the other fields of nuclear physics is given.

Coulomb breakup of unstable neutron-rich carbon isotopes 15,17 C has been studied at energies around ∼500–600 MeV/nucleon. Non-resonant low-lying dipole strength is observed in these isotopes which can be explained by a direct breakup mechanism. In addition to the decay neutron from excited projectile, γ-rays emitted from excited fragments after Coulomb breakup are measured in coincidence, giving access to quantitative spectroscopic information. The spectroscopic factor deduced for a valence neutron occupying the s1/2 level in the 15C ground state is consistent with that obtained earlier from (d,p) transfer reactions. The analysis for Coulomb breakup of 17C shows that most of the cross section yields the 16C core in excited states. The predominant ground-state configuration of 17C is found to be 16 C (2 + )⊗ν s,d .

We have measured the interaction cross sections (σI) of 31–40Ar and 31–37Cl on carbon targets at energies of around 950 A MeV. The effective matter radii for these nuclei were deduced by a Glauber-model analysis. Combining our matter radii with measured charge radii for Ar isotopes, we could deduce the proton-skin thicknesses for the 32–40Ar isotopes, which were found to increase monotonically with decreasing neutron number. The larger radius of the proton drip-line nucleus 31Ar suggests an anomalous structure for this nucleus. In addition, using NaI(Tl) arrays surrounding the carbon target, we measured γ-rays emitted from excited states in these isotopes. In this way we could deduce the upper limits for the inelastic cross sections (σinela) on carbon targets at energies of around 950 A MeV.

Neutron deficient nuclei near Sn-100 have been produced by fragmentation of a 1 (.) A GeV Sn-112 beam. The fragments were separated, identified and stopped in a highly segmented silicon strip detector stack. This detector measured the total energy of emitted beta(+)-particles. gamma-radiation was measured with surrounding detectors. The half-lives for many nuclides have been determined for the first time and give important information for the following topics: For the heaviest particle-stable odd-odd nuclei Rh-90, Ag-94 and In-98 we observed for the first time fast beta-decays, compatible with superallowed Fermi transitions and confirmed such decays for 78y, 82 Nb and Tc. We have also observed 'long-lived T = 0 states in some of these nuclei. We measured the half-lives of all rp-process waiting-point nuclei from _Zr up to addition we find the proton drip line nucleus Y-77 to decay dominantly via beta-decay, To study the Gamov-Teller strength in the beta-decay near the doubly magic Sn-102 we measured the half-life, beta- and gamma-spectrum of Sn-102. We propose a level scheme for the daughter nuclide In-102 and deduce the Qamov-Teller strength (B-GT = 4.0 +/- 0.6). This is one of the largest values known. (Less)

The charge-exchange contribution can dominate the energy-loss straggling of partially stripped heavy ions depending on the charge-changing cross sections and the partial stopping powers. We have studied the energy-loss straggling of few-electron uranium ions in different solids in the energy range of (200–1000) MeV/u. Our experimental data are compared with a new model taking into account realistic screening for relativistic scattering of target electrons at close impacts to derive partial stopping powers. Screening of the projectile nucleus by inner-shell electrons reduces the charge-exchange straggling compared to that pertaining to a point-like charge distribution.

We present results from two methods of direct mass measurements of relativistic exotic nuclei stored in the storage ring ESR. Schottky Mass Spectrometry (SMS) with electron-cooled ions is well suited for long-lived nuclei ( T 1/2 ⩾10 s), and the Isochronous mass measurements (IMS) for hot fragments ( T 1/2 ⩾1 μs). In addition, SMS provides information on nuclear lifetime for bare and highly ionized atoms.

Coulomb break up of the neutron-rich 15,17 C and 17–22 O isotopes has been studied experimentally using secondary beams at energies of 500–600 MeV/u. A comparison between differential cross sections, d σ/ d E ∗ , with that obtained from a binary model shows that the main ground-state configuration of 15 C is 14 C(0 + )⊗ ν S 1/2 as expected. For 17 C, our preliminary data analysis reveals that the predominant (∼64%) configuration of the ground state is 16 C(2 + )⊗ ν s , d . For 17–22 O, the low-lying E1 strength amounts up to about 12% of the energy weighted sum rule strength depending on neutron number. The energy weighted E1 strength (integrated up to 15 MeV excitation energy) increases up to 20 O then decreases for 21,22 O. These data are compared to a shell model calculation.

The 26Si(p; γ)27P reaction, which might play an important role in the rp process, was studied by the Coulomb Dissociation method. The experiment was performed at GSI, Darmstadt. A secondary 27P ion beam of 500 MeV/nucleon was directed onto a Pb target. From this experiment, the Coulomb Dissociation cross section, σ Coulex , will be deduced and then converted to the photoabsorption cross section, σ photo , and the radiativecapture cross section, σ cap . Also information on the structure of 27P will be obtained. The analysis is in progress.

We report on the first observation of the unbound proton-rich nucleus 15Ne. Its ground state and first excited state were populated in two-neutron knockout reactions from a beam of 500 MeV/u 17Ne. The 15Ne ground state is found to be unbound by 2.522(66) MeV. The decay proceeds directly to 13O with simultaneous two-proton emission. No evidence for sequential decay via the energetically allowed 2- and 1- states in 14F is observed. The 15Ne ground state is shown to have a strong configuration with two protons in the (sd) shell around 13O with a 63(5)% (1s1/2)2 component.

F. Wamers et al.; 4 pags.; 2 figs. Open Access funded by Creative Commons Atribution Licence 2.0, We have studied one-proton-removal reactions of about 500 MeV/u17Ne beams on a carbon target at the R3B/LAND setup at GSI by detecting beam-like 15Op and determining their relative-energy distribution. We exclusively selected the removal of a 17Ne halo proton, and the Glauber-model analysis of the 16F momentum distribution resulted in an s 2 contribution in the 17Ne ground state of about 40 %. C Owned by the authors, published by EDP Sciences, 2014, This work was supported by the Alliance Program of the Helmholtz Association (HA216/EMMI), by the German Federal Ministry for Education and Research (BMBF) (project 05P12RDFN8) by HIC for FAIR, by Eurons (European Commission contract no. 506065), and by GSI.