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Interaction cross sections (σI) for Ne isotopes from the stability line to the vicinity of neutron-drip line have been measured using the RIBF facility at RIKEN. Measurements have been performed for 20–32Ne on C target at energies around 240 MeV/nucleon. A large enhancement of σI beyond the systematics of stable nuclei have been observed for neutron-rich Ne isotopes. The possible halo structures with lower orbital angular momentum for 29,31Ne are discussed by the preliminary analysis. [ABSTRACT FROM AUTHOR]

The first results from a series of experiments focused on the study of the internal structure of nuclei at the extremes of N:Z ratio using isomer spectroscopy are reported. These experiments represent the first of the Stopped Beam section of the Rare Isotopes Investigations at GSI (RIS-ING) project. Exotic nuclei were synthesized using relativistic projectile fragmentation of ∼ 500 → 1000 MeV/u beams of 107Ag, 208Pb, 136Xe and 58Ni, or fission of 750 MeV/u 238U provided by the SIS synchrotron at GSI. A detailed description of the RISING stopped beam set up is given, together with a report of the performance of the associated gamma-ray spectrometer array. Selected results of the first experimental campaign are presented together with a discussion on the use of isomeric spectroscopy to study GeV range nuclear fragmentation. Details on future research plans of this collaboration are also outlined. [ABSTRACT FROM AUTHOR]

Projectile fragments separated in flight with the FRS have been injected into the storage ring ESR. Operating the ESR in the isochronous mode has enabled high-resolution mass measurements of short-lived isotopes. Already in our pilot experiments the Isochronous Mass Spectrometry (IMS) has provided accurate results for a restricted isotope range in the neighborhood of a selected isotope characterized by the best isochronous condition. In the present experiment this restriction has been overcome by precise external magnetic rigidity determination (1.5·10–4) at the dispersive midplane of the FRS. In this way the mass resolving power for neutron-rich fission fragments covering a large mass-over-charge ratio in one spectrum has been improved by up to one order of magnitude and the accuracy by more than a factor of two. [ABSTRACT FROM AUTHOR]

Abstract: A review and recent progress are presented from experiments on masses and lifetimes of bare and few-electron exotic nuclei at GSI. Relativistic rare isotopes produced via projectile fragmentation and fission were separated in flight by the fragment separator FRS and injected into the storage ring ESR. This worldwide unique experimental method gives access to all fragments with half-lives down to the microsecond range. The great research potential is demonstrated by the discovery of new isotopes along with simultaneous mass and lifetime measurements. Single particle decay measurements and the continuous recording of both stored mother and daughter nuclei open up a new era for nuclear spectroscopy. The study of bare and few-electron nuclei has also important astrophysical relevance with respect to the hot stellar conditions where reactions and decay are influenced by the degree of atomic ionization. The future international NUSTAR facility at FAIR consisting of a new large-acceptance in-flight separator (Super-FRS) and a dedicated storage ring system (CR–RESR–NESR) will be an ideal tool to study nuclei with new probes and to investigate the majority of relevant r- and rp-process nuclei which are not in reach with the present-day facilities. [Copyright &y& Elsevier]

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 Iπ = 1/2+ was deduced for the 23O ground state. This result solved the existent experimental discrepancy. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Absolute differential cross-sections for elastic p6He and p8He scattering were measured in inverse kinematics with secondary beams. In order to supplement data taken for small-angle scattering, differential cross-sections for higher momentum transfer were measured using liquid hydrogen target. Both data sets were analyzed together. They have permitted to deduce the radial shape of the nuclear matter distributions and the root-mean-square radii with the help of Glauber theory. In addition to a phenomenological analysis, used already in the previous work, a model-independent analysis with a help of a Sum-Of-Gaussians (SOG) method has been performed. The experimental p6,8He elastic scattering cross-sections have also been compared with the predictions from various theoretical nuclear models. [ABSTRACT FROM AUTHOR]

Graphical abstract: Display Omitted Highlights: [•] We present the prospects for rare-isotope storage-ring measurements at FAIR. [•] A summary of present storage-ring capabilities is presented. [•] Access to the most exotic nuclides is provided using projectile fragmentation. [•] Masses and decay modes can be determined for highly-charged single ions. [•] Novel interactions at the atomic–nuclear interface are discussed. [ABSTRACT FROM AUTHOR]

BigRIPS is a powerful two-stage in-flight separator for the research with exotic nuclei studied in frontier experiments since more than a decade. The ion-optical system is very versatile due to the multi-stage structure of BigRIPS combined with the ZeroDegree spectrometer or the Superconducting Ring Cyclotron (SRC). Various optical modes can be flexibly realized according to the purpose of experiments. Two categories of developments are presented here. One is a new operating mode of BigRIPS aiming at higher ion-optical resolving power. BigRIPS itself has a two-stage structure. Spatial isotope separation is made at both the first and second stages. In the standard operating mode of BigRIPS, at the second stage the two spatial separations with energy degraders are subtractive in their resolving powers. Here, we present the additive mode. With the resulting increased spatial separation power, the isotopic background can be substantially reduced. Higher ion-optical resolving powers of the first and second BigRIPS degrader stages are also investigated with the goals to reduce further the background and to yield access to new isotopes of heavier elements. The other development is a dispersion-matched system with BigRIPS for high-resolution spectrometer experiments. The BigRIPS and ZeroDegree spectrometer are presently two independent, coupled achromatic systems. A new dispersion-matched mode of BigRIPS and ZeroDegree will enable novel experiments. For high-resolution spectroscopy experiments with high-intensity light projectiles, SRC and BigRIPS can be operated as a dispersion-matched system. The described different ion-optical developments are a base for a new category of experiments exploring exotic nuclei and mesic atoms. Characteristic future experiments with these new ion-optical developments are exemplified in this report. [ABSTRACT FROM AUTHOR]

Abstract A thick neutron skin emerges from the first determination of root mean square radii of the proton distributions for 17−22N from charge changing cross section measurements around 900 A MeV at GSI. Neutron halo effects are signalled for 22N from an increase in the proton and matter radii. The radii suggest an unconventional shell gap at N = 14 arising from the attractive proton–neutron tensor interaction, in good agreement with shell model calculations. Ab initio , in-medium similarity re-normalization group, calculations with a state-of-the-art chiral nucleon–nucleon and three-nucleon interaction reproduce well the data approaching the neutron drip-line isotopes but are challenged in explaining the complete isotopic trend of the radii. [ABSTRACT FROM AUTHOR]

The HISPEC/DESPEC collaboration envisages long experimental campaigns exploiting the expected beam performances of Super-FRS. The experiments will be performed at the Low-Energy Branch of the upcoming FAIR and will focus on the physics of exotic isotopes, primarily in the heavy neutron-rich region. The goal of the HISPEC/DESPEC experimental campaigns is to explore the excitation and decay properties of rare isotopes produced via fragmentation and fission. First rare-isotope beam simulations of representative future HISPEC/DESPEC experimental cases are presented. The simulations provide an insight into the forthcoming state-of-art experiments in the future FAIR facility. [ABSTRACT FROM AUTHOR]

Abstract: In the present work, the differential cross sections for small-angle proton elastic scattering on the 12,14Be nuclei were measured in inverse kinematics, using secondary radioactive beams with energies near 700 MeV/u produced with the fragment separator FRS at GSI. The main part of the experimental setup was the active target IKAR, which was used simultaneously as a target and a detector for the recoil protons. Auxiliary detectors for projectile tracking and isotope identification completed the setup. The measured differential cross sections were analyzed using the Glauber multiple-scattering theory. For the evaluation of the data several phenomenological nuclear-matter density parametrizations and a sum of Gaussian parametrization were used. The nuclear-matter radii and radial density distributions of the isotopes 12,14Be were deduced. Extended nuclear-matter density distributions were observed in both isotopes, and the halo structure of 14Be was confirmed. The results were also compared with microscopic few-body and fermionic molecular dynamics model calculations concerning the structure of these neutron-rich nuclei. [Copyright &y& Elsevier]

Abstract: The production cross-sections of proton-rich protactinium and thorium isotopes have been investigated for the fragmentation of 1 A GeV 238U 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 first observation of the new isotopes 208Th and 211Pa is presented. [Copyright &y& Elsevier]

The computer simulations of the angular distributions of low-Z relativistic isotopes channeled in a half-wavelength-crystal (HWC) revealed that at equal beam energy, crystal thickness and its alignment, the HWC channeling is sensitive to a mass number A of the low-Z isotope. That means, besides well-known applications of relativistic channeling for beam deflection and splitting, probably the new one is possible – light isotopes mass filter. [ABSTRACT FROM AUTHOR]