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5 pags., 4 figs., Excited states in Zn were populated following one-neutron removal from a Zn beam impinging on a Be target at intermediate energies in an experiment conducted at the Radioactive Isotope Beam Factory at RIKEN. Three γ rays were observed and tentatively assigned to the 6→4→2→0 yrast sequence. This turns Zn into the heaviest T=−2 nucleus in which excited states are known. The excitation-energy differences between these levels and the isobaric analogue states in the T=+2 mirror partner, Fe, are compared with large-scale shell-model calculations considering the full pf valence space and various isospin-breaking contributions. This comparison, together with an analysis of the mirror energy differences in the A=58, T=±1 pair Zn and Ni, provides valuable information with respect to the size of the monopole radial and the isovector multipole isospin-breaking terms in the region above doubly-magic Ni., We thank the RIKEN Nishina Center accelerator staff and the BigRIPS team for providing excellent beams to the experiment. This work was supported by the Spanish Ministerio de Ciencia e Inno- vación under contracts FPA2017-84756-C4-2-P, PGC-2018-94583, and SEV-2016-0597, the Swedish Research Council (Vetenskap- srådet, VR 2016-3969), and the UK Science and Technology Facil- ities Council (STFC) under grants ST/L005727/1 and ST/P003885/1. FB is supported by the RIKEN Special Postdoctoral Researcher Pro- gram

At low-energy nuclear physics facilities, the in-flight fragmentation method is often employed to produce radioactive ion beams. This technique often involves a stable ion beam at high intensity and a gas cell target. Since the parameters for the production reaction are usually chosen to take advantage of a large cross section of the resonance reaction, a slight change in the center-of-mass energy due to the reduced target density may significantly affect the rare isotope production rate. Therefore, to estimate the heating effect due to beam particles on the target thickness, a new and more comprehensive semi-empirical model is developed by employing a heating factor function. The estimated heating factors were consistent with experimental data, which were obtained from various reaction measurements at wide ranges of heat densities.

We measured the $^{8}\mathrm{Li}(p,p)^{8}\mathrm{Li}$, $^{8}\mathrm{Li}(p,d)^{7}\mathrm{Li}$, and $^{8}\mathrm{Li}(p,\ensuremath{\alpha})^{5}\mathrm{He}$ reactions at low energies using the thick target inverse kinematics method, with a polyethylene ${[{\mathrm{CH}}_{2}]}_{n}$ target and a radioactive $^{8}\mathrm{Li}$ beam available at the Radioactive Ion Beams in Brazil facility of S\~ao Paulo. By measuring simultaneously several reaction channels $(p,p)$, $(p,d)$, and $(p,\ensuremath{\alpha})$, the still uncertain high-lying resonances of $^{9}\mathrm{Be}$, close to the proton threshold, can be studied and their parameters, such as energy, width, and spin parity can be more reliably determined. The experimental excitation functions of the reactions $^{8}\mathrm{Li}(p,p)^{8}\mathrm{Li}$, $^{8}\mathrm{Li}(p,d)^{7}\mathrm{Li}$, and $^{8}\mathrm{Li}(p,\ensuremath{\alpha})^{5}\mathrm{He}$ were analyzed using the $R$-matrix theory, which allows us to infer the properties of the resonances. Multichannel $R$-matrix analysis provides evidence for a significant clustering in the $(p,d)$ channel. The experimental data and the multichannel $R$-matrix analysis will be presented.

International audience; In the framework of the SPIRAL1 (SP1) facility, the R&D of charge breeding techniqueis of primary interest for optimizing the yields of radioactive ion beams (RIBs). This techniqueinvolves the transformation of mono-charged ion beams into multi-charged ion beams by operatingan SPIRAL1 Electron Cyclotron Resonance charge breeder (CB). During the SPIRAL1 commissioning, experimental studies have been performed in order to understand the transport of the beamthrough the SP1 CB with and without ECR plasma. Numerical simulations including ion optics and some ECR plasma features have been developed to evaluate ion losses during the ion transport through the SP1 CB with and without a simplified model of the ECR plasma.

In the previous chapter, it was discussed that for non-radioactive ion beams, the lifetimes depend on the atomic charge-changing interactions between the ion beam and residual-gas components. In the case of radioactive ion beams, the mean lifetimes depend in addition on the nuclear properties of accelerated ions, and hence, the total mean lifetime comprises both atomic and nuclear components: $$\begin{aligned} \frac{1}{\tau } = \frac{1}{\tau _{\mathrm{atomic}}} + \frac{1}{\tau _{\mathrm{nuclear}}}, \end{aligned}$$ (10.1) or equivalently: $$\begin{aligned} \lambda = \lambda _{\mathrm{atomic}} + \lambda _{\mathrm{nuclear}}, \end{aligned}$$ (10.2) where \(\lambda = 1/\tau \) is the total decay rate. Each decay components may have several terms, which correspond to different decay channels (e.g., \(\alpha -, \,\,\beta ^+-, \,\,\beta ^--\)decay, fission, etc.) and/or state transitions (e.g., nuclear ground-ground state transitions, ground-excited state transitions, etc.), so one can define: $$\begin{aligned} \lambda _{\mathrm{nuclear}} = \sum _{\mathrm{all\,\, channels\,\, }i} \lambda _{i}. \end{aligned}$$ (10.3) The individual decay rate depends on the underlying processes. In the following sections, we describe mechanisms of the decay rates, or mean lifetimes, due to the nuclear reactions.

2.45 GHz ECR ion sources are widely used for production of protons, single charged heavy ions and secondary radioactive ion beams. This paper describes the development of a compact ECR ion source based on 2.45 GHz coaxial resonator. The first results of extracted current measurements at different resonator configuration as a function of UHF frequency, power and gas flow are presented.

NMR detected by radioactive beta decay, β-NMR, is undergoing a renaissance largely due to the availability of high intensity low energy beams of the most common probe ion, Li+8, and dedicated facilities for materials research. The radioactive detection scheme, combined with the low energy ion beam, enable depth resolved NMR measurements in crystals, thin films and multilayers on depth scales of 2-200 nm. After a brief historical introduction, technical aspects of implanted-ion β-NMR are presented, followed by a review of recent applications to a wide range of solids.

Polarized rare isotope (RI) beams have been designed at the Rare Isotope Science Project (RISP) for the study of the nuclear-structure, nuclear-reaction and astrophysics experiments. A powerful method has been adopted for this work — the production of polarized RI beams via projectile fragmentation. The in-flight system line was designed for this purpose at the RISP by using the projectile fragmentation method. The working principle, schematic design and experiments to be performed at the RISP will be presented.

By using para-hydrogen and a mechanical press made of neodymium magnets, we have succeeded in making a 1-mm-thick and 30-mm-diameter solid hydrogen target (SHT), and have measured elastic scattering of protons with radioactive ion beams at 300 MeV/u. We also succeeded in making not only a 0.5-mm-thick and 10-mm-diameter SHT but also a 2-mm-thick and 30-mm-diameter SHT to study excited-state properties of nuclei via (p,p′) reactions, and quasi-free (p,pα) reactions at intermediate energies. The ortho–para converter and the simple mechanical press show possibilities for making SHTs which have various radii and thicknesses.

A new method has been developed to detect and identify isomeric states produced in intermediate beam-energy reactions with secondary radioactive beams. Event-by-event identification of the reaction products allows for an unambiguous assignment of isomeric states to certain nuclei produced in fragmentation reactions. This versatile device allows for the identification of isomeric states with lifetimes between 100 ns and several ms. Combined prompt and delayed γ-ray spectroscopy give detailed information on the level schemes of exotic nuclei. This is particularly important in measurements of exclusive reaction cross-sections to several final states in the residue nucleus.

Background: The $^{17}\mathrm{F}(p,\ensuremath{\gamma})^{18}\mathrm{Ne}$ reaction is part of the astrophysical ``hot CNO'' cycles that are important in astrophysical environments like novas. Its thermal reaction rate is low owing to the relatively high energy of the resonances and therefore is dominated by direct, nonresonant capture in stellar environments at temperatures below 0.4 GK.Purpose: An experimental method is established to extract the proton strength to bound and unbound states in experiments with radioactive ion beams and to determine the parameters of direct and resonant capture in the $^{17}\mathrm{F}(p,\ensuremath{\gamma})^{18}\mathrm{Ne}$ reaction.Method: The $^{17}\mathrm{F}(d,n)^{18}\mathrm{Ne}$ reaction is measured in inverse kinematics using a beam of the short-lived isotope $^{17}\mathrm{F}$ and a compact setup of neutron, proton, $\ensuremath{\gamma}$-ray, and heavy-ion detectors called resoneut.Results: The spectroscopic factors for the lowest $l=0$ proton resonances at ${\mathrm{E}}_{\mathrm{c}.\mathrm{m}.}=0.60$ and 1.17 MeV are determined, yielding results consistent within $1.4\ensuremath{\sigma}$ of previous proton elastic-scattering measurements. The asymptotic normalization coefficients of the bound ${2}_{1}^{+}$ and ${2}_{2}^{+}$ states in $^{18}\mathrm{Ne}$ are determined and the resulting direct-capture reaction rates are extracted.Conclusions: The direct-capture component of the $^{17}\mathrm{F}(p,\ensuremath{\gamma})^{18}\mathrm{Ne}$ reaction is determined for the first time from experimental data on $^{18}\mathrm{Ne}$.

We present $^{8}\mathrm{B}+^{27}\mathrm{Al}$ elastic scattering angular distributions for the proton-halo nucleus $^{8}\mathrm{B}$ at two energies above the Coulomb barrier, namely ${E}_{\mathrm{lab}}=15.3$ and 21.7 MeV. The experiments were performed in the Radioactive Ion Beams in Brasil facility (RIBRAS) in S\~ao Paulo, and in the TwinSol facility at the University of Notre Dame, USA. The angular distributions were measured in the angular range of 15--80 degrees. Optical model and continuum discretized coupled channels calculations were performed, and the total reaction cross sections were derived. A comparison of the $^{8}\mathrm{B}+^{27}\mathrm{Al}$ total reaction cross sections with similar systems including exotic, weakly bound, and tightly bound projectiles impinging on the same target is presented.

The neutron-deficient ${}^{\mathrm{196,198}}$Pb isotopes have been studied in Coulomb-excitation experiments employing the Miniball γ-ray spectrometer and radioactive ion beams from the REX-ISOLDE post-accelerator at CERN. The reduced transition probabilities of the first excited 2+ states in 196Pb and 198Pb nuclei have been measured for the first time. Values of $B(E2)={18.2}_{-4.1}^{+4.8}$ W.u. and $B(E2)={13.1}_{-3.5}^{+4.9}$ W.u., were obtained, respectively. The experiment sheds light on the development of collectivity when moving from the regime governed by the generalised seniority scheme to a region, where intruding structures, associated with different deformed shapes, start to come down in energy and approach the spherical ground state. journal_title: Journal of Physics G: Nuclear and Particle Physics article_type: paper article_title: Collectivity in ${}^{\mathrm{196,198}}$Pb isotopes probed in Coulomb-excitation experiments at REX-ISOLDE copyright_information: © 2017 IOP Publishing Ltd date_received: 2016-10-31 date_accepted: 2017-03-17 date_epub: 2017-05-03 ispartof: Journal of Physics G, Nuclear and Particle Physics vol:44 issue:6 status: published

Reactions on certain proton-rich, radioactive nuclei have been shown to have a significant influence on X-ray bursts. We provide an overview of two recent measurements of important X-ray burst reactions using in-flight radioactive ion beams from the RESOLUT facility at the J. D. Fox Superconducting Accelerator Laboratory at Florida State University. The 17 F(d,n) 18 Ne reaction was measured, and Asymptotic Normalization Coefficients were extracted for bound states in 18 Ne that determine the direct-capture cross section dominating the 17 F(p, γ ) 18 Ne reaction rate for T≲ 0.45 GK. Unbound resonant states were also studied, and the single-particle strength for the 4.523-MeV (3 + ) state was found to be consistent with previous results. The 19 Ne(d,n) 20 Na proton transfer reaction was used to study resonances in the 19 Ne(p, γ ) 20 Na reaction. The most important 2.65-MeV state in 20 Na was observed to decay by proton emission to both the ground and first-excited states in 19 Ne, providing strong evidence for a 3 + spin assignment and indicating that proton capture on the thermally-populated first-excited state in 19 Ne is an important contributor to the 19 Ne(p, γ ) 20 Na reaction rate.

Radioactive ion beams (RIB) have been recently accelerated for the first time at the VECC-RIB facility. Beams of 14 O (71 s), 42 K (12.4 h), 43 K (22 h) and 41 Ar (1.8 h) have been produced by bombarding 1 atm nitrogen and argon gas targets with 1 micro-ampere proton and alpha particle beams from the K130 cyclotron. Radioactive atoms were transported 15 m away to the ECR ion-source using a gas-jet transport system. Typical measured intensity of RIB at the separator focal plane is few times 10 3 pps. About 3300 pps of 1.4 MeV 14 O was measured after acceleration through a 3.4 m long RFQ linac. The details of the gas-jet coupled ECR and RIB production experiments are presented.

In this review on target and ion sources for ISOL (Isotope Separation OnLine) beams, important developments from the past five years are highlighted. While at precedent EMIS conferences, a particular focus was given to a single topics, for instance specifically on ion sources or on chemical purification techniques, here each of the important elements present in an ISOL production unit is discussed. Fast diffusing nanomaterials, uranium-based targets, high power targets for next generation facilities, purification by selective adsorption, new ion sources are all part of this review. For each of these selected topics, the reported results lead to significant gains in intensity, purity, or quality of the delivered beam, or in the production of new isotope beams. Often the outcome resulted from the combination of original ideas with state-of-the-art investigations; this was carried out using very different scientific disciplines, leading to understanding of the underlying chemical or physical mechanisms at the origin of the improvements.

Spin-degrees of freedom play a significant role in exotic nuclei. Scattering with polarized protons has potential as a powerful tool to explore the spin effects in nuclei. This lecture note discusses the background, current status, and future prospects of experimental studies with spin polarized targets and radioactive ion beams., Comment: Lecture note of "Rewriting Nuclear Physics textbooks: 30 years with radioactive ion beam physics", July 2015, Pisa, Italy

We investigated the reaction dynamics induced by the 7Be,8B+208Pb collisions at energies around the Coulomb barrier. Charged particles originated by both the col- lisions were detected by means of 6 ΔE-Eres telescopes of a newly developed detector array. Experimental data were analysed within the framework of the Optical Model and the total reaction cross-sections were compared together and with the 6,7Li+208Pb colli-sion data. According to the preliminary results, 7Be nucleus reactivity is rather similar to the 7Li one whereas the 8B+208Pb total reaction cross section appears to be much larger than those measured for reactions induced by the other weakly-bound projectiles on the same target.

A small volume cryogenic ion guide has been characterized at the IGISOL facility, Jyvaskyla, as a prototype to verify whether there are any major obstacles to the use of high-density cryogenic helium gas for the stopping and extraction of high-energy ions from a large volume cryogenic ion catcher. The expected temperature scaling of the mass flow through the ion guide has been confirmed, showing that for the same helium density, the differential pumping requirements are less stringent for cryogenic operation. At 90 K a clear reduction in the mass-analyzed impurities is achieved, although lower temperatures are required to freeze out oxygen and nitrogen. This is supported by the reduction in the measured secondary beam current exiting the ion guide in the presence of primary beam. Despite this reduction, the activity of Na-20 (t(1/2) = 446 ms) at primary beam intensities above 1 mu A is rather similar to that achieved at room temperature. A constant extraction efficiency of a beam of Ni-58(+) ions, with initial energy 340 MeV, spanned approximately five orders of magnitude of ionization-rate density. In summary, the cryogenic ion guide is a promising new tool to support the improvement of low-energy beam production at the IGISOL-4 facility which is expected to be operational in 2012. (C) 2012 Elsevier B.V. All rights reserved.

The 253.3–keV excited state located in 93 Rb was studied at the Holifield Radioactive Ion Beam Facility in Oak Ridge. This state, described as isomeric in databases, was populated in the decay of 93 Kr produced by proton–induced fission of 238 U and isolated using the isotope separation on–line technique. We report that the 253.3–keV level does not reveal isomerism and the upper limit of the half-life from our measurement is 4 ns. Our findings are supported by previously reported results that were not taken into account in the latest nuclear databases.

The capture-fission cross-section is measured for the collision of the massive nucleus 132Sn with 96Zr at near-barrier energies and compared with the collision of 124Sn with 96Zr. This study gives insight into fusion enhancement and hindrance in systems involving neutron-rich nuclei. The dinuclear system model (DNS) calculations describe the excitation function reasonably well and if we use the barrier heights predicted by this model we can conclude that fusion hindrance (represented by extra push energy) is greater for the more neutron-rich systems.

The FRIBs facility at the Laboratori Nazionali del Sud produces since a few years, Radioactive Ion Beams (RIBs) at intermediate energies, by projectile fragmentation. The possibility of using the produced RIBs as secondary beams in nuclear physics experiments by applying the tagging technique, i.e. the identification, event-by-event, in charge, mass and energy of each ion of the RIBs cocktail selected by the fragment separator, before it interacts with the secondary target, has been demonstrated. Status and perspectives of the facility are discussed.

We have investigated the survival and transport efficiency of Ra-219 ions emitted by a Ra-223 source in high-density cryogenic helium gas, with ionisation of the gas induced by a proton beam. The combined efficiency of ion survival and transport by an applied electric field was measured as a function of ionisation rate density for electric fields up to 160 V/cm and for three temperature and density combinations: 77 K, 0.18 mg/cm(3), 10 K, 0.18 mg/cm(3) and 10 K, 0.54 mg/cm(3). At low beam intensity or high electric field, an efficiency of 30%, is obtained, confirming earlier results. A sharp drop in efficiency is observed at a "threshold" ionisation rate density which increases with the square of the applied electric field. At 160 V/cm, the efficiency stays above 10% up to an ionisation rate density of 10(12) ion-electron pairs/cm(3)/s. The observed behaviour is understood as the result of shielding of the applied field by the weak plasma created by the proton beam: it counteracts the effective transport of ions and electrons, leading to recombination between the two. We conclude that cryogenic helium gas at high-density and high electric field is a promising medium for the transformation of very high-energy ions into low-energy ones. (c) 2008 Elsevier B.V. All rights reserved.

We developed a Monte-Carlo code for describing the reaction kinematics of the two-body direct processes employed of the EXOTIC beam-line of the Laboratori Nazionali di Legnaro (LNL) for the production of light weakly bound radioactive ion beams at energies of a few MeV/u. The program calculates the phase-space distribution of both primary and secondary beams at the target exit and uses these quantities to optimize the secondary beam selection with the EXOTIC spectrometer. The calculations have been performed and compared with the available experimental data for two reactions: (1)H(2)((17)O, (17)F)n and (3)He((6)Li, (8)B)n. (c) 2008 Elsevier B.V. All rights reserved.

The FRIBs facility at the Laboratori Nazionali del Sud produces, since a few years, radioactive ion beams (RIBs) at intermediate energies, by projectile fragmentation. The possibility of using the produced RIBs as secondary beams in nuclear physics experiments by applying the tagging technique, i.e. the identification, event-by-event, in charge, mass and energy of each ion of the RIBs cocktail selected by the fragment separator, before it interacts with the secondary target, has been demonstrated. Status and perspectives of the facility are discussed.

International audience; As one of the fashionable techniques for nuclear spectroscopy experiments, the beam manipulation in gas-filled Penning traps permits the accurate measurement of some of the ground state properties of exotic nuclides. It was recently applied using REXTRAP for the measurement of the half-life of 38Ca, one of the 0+ → 0+ β-decaying nuclide of interest for the determination of the Ft value for super-allowed transitions, and the test of the unitarity of the CKM matrix. The experimental setup and the original method of beam purification adopted for this measurement is presented.

The 8 Li + 4 He → 11 B + n reaction at E cm 2 MeV is a process of relevant astrophysical interest for which a remarkable experimental discrepancy between inclusive and exclusive cross-section measurements exists. In this Letter, a new inclusive neutron measurement at E cm = 1.05 ± 0.16 MeV is given. The radioactive 8 Li beam was delivered by the EXCYT facility. The cross section was determined by a low-background measurement of the time correlation between the 8 Li projectile arrival to the target and the following neutron capture in a threshold-less 4 π thermalization counter. This new data strengthens the reliability of the previous inclusive reaction cross-section data and altogether are consistent with a significant population of 11 B levels at high excitation energy.

The availability of accelerated fission fragments at HRIBF allows us to study fusion reactions where one of the reactants is a short-lived exotic nucleus. Most interesting in this respect are entrance channels involving neutron-rich target and projectile – where enhanced survival probability of the compound system may allow the synthesis of heavier system. Much depends though on the dynamic evolution of the captured nuclei into a compound nucleus and the ensuing competition between fission and evaporation residue decay modes. Our studies of fusion between heavy neutron-rich nuclei are aimed at acquiring data that will lead to the understanding and eventually the ability to predict the probabilities for these different processes.

The production of Radioactive Ion Beams (RIBs) at intermediate energy by the In-Flight method (Projectile Fragmentation) and their transport along the beam lines were successfully achieved at the Lab- oratori Nazionali del Sud-Catania. In particular the yield of the fragmentation products of 12 C, 20 Ne, 40 Ar, 58 Ni projectiles at incident energies in the range 40 to 62 AMeV was studied. RIBs rates up to 10 5 ions/sec were estimated for a primary beam current of 500 enA. The ∆E-ToF identification method was applied to "tag" event-by-event the RIBs selected by the LNS Fragment Separator among the fragmentation products of the primary projectile. The feasibility of different contemporaneous measurements with "tagged" RIBs, was proved by the results of two explorative experiments.

We report here on experiments with radioactive 21 Na and 7 Be beams performed by Colorado School of Mines students at the ISAC facility of TRIUMF and the Holifield Radioactive Ion Beam Facility (HRIBF) of ORNL. At TRIUMF, the DRAGON recoil separator and its segmented BGO array were used to investigate higher energy resonances in the reaction H( 21 Na, γ) 22 Mg. Using the HRIBF we performed an experiment with a 7 Be ion beam to measure scattering off Hydrogen and Carbon. Both elastic 7 Be + p scattering and for the first time resonant inelastic scattering 7 Be(p, p′) 7 Be ∗ were observed.

Preliminary results from the study of collectivity and single-particle structure in neutron-rich nuclei are presented from selected experiments. The experiments discussed here employed the MINIBALL Germanium detector array for gamma-ray detection. Coulomb-excitation experiments at REX-ISOLDE focused on the collectivity of Cd and Xe isotopes near 132Sn as well as the shell structure near N = 20 , N = 40 , and N = 50 . Another experiment was performed to probe the single-particle structure of 47Ca, 55Ti, and 73Cu at the GSI Fragmentseparator, using single-nucleon knock-out reactions at relativistic energies.

The elastic scattering of the radioactive halo nucleus 6He on 27Al target was measured at four energies close to the Coulomb barrier using the RIBRAS (Radioactive Ion Beams in Brazil) facility. The Sao Paulo Potential(SPP) was used and its diffuseness and imaginary strength were adjusted to fit the elastic scattering angular distributions. Reaction cross-sections were extracted from the optical model fits. The reduced reaction cross-sections of 6He on 27Al are similar to those for stable, weakly bound projectiles as {6,7}Li, 9Be and larger than stable, tightly bound projectile as 16O on 27Al., 7 pages, 1 table, 3 figures

Based on the technique of fragment‐induced spin polarization combined with the β‐NMR method, a series of experiments has been carried out at RIKEN for the nuclear‐moment measurement of light unstable nuclei. The measurement will be extended further in the RIKEN RIBF project, where radioactive‐isotope beams in the medium‐ and heavy‐mass regions will be produced at higher energies and with higher intensities compared with the RARF facility. Measurements of the isomeric‐state nuclear moments of unstable nuclei will be started with BigRIPS by utilizing fragment‐induced spin‐orientation phenomena. Also, an upgrade program of the existing fragment separator RIPS is proposed in the phase‐II program of RIBF. Then, intense beams will be delivered to RIPS at E ∼ 115 A MeV. This energy region is useful, not only because spin orientation is produced in the PF reaction but also they can be implanted into sample materials with limited thickness.

The results from a particle-in-cell code developed to describe the drifting of ions in an ionized buffer gas are described. The rate of ionization was found to have a dramatic effect on the collection efficiency of the heavy ions and results of the calculations agree well with recent observations.

The odd–odd nucleus 30Na is studied via a one-proton, one-proton–one-neutron and one-neutron removal reaction using an intermediate-energy 31Mg, 32Mg and 31Na radioactive ion beam, respectively. Combining high-resolution γ-ray spectroscopy with the selectivity of the three reaction mechanisms, we are able to distinguish multiple particle–hole configurations. Negative-parity states in 30Na are observed for the first time, providing an important measure of the excitation of the 1p1h/3p3h configuration and hence the sd–pf shell gap. The extracted band structures and level energies serve as invaluable input for the theoretical refinement of the effective interactions used in this region.

The study of low-energy reactions with radioactive-ion beams has been greatly enhanced by the recent use of active-target detectors, which have high efficiency and low thresholds to detect low-energy charged-particle decays. Both of these features have been used in experiments with the Prototype Active-Target Time-Projection Chamber to study α -cluster structure in unstable nuclei and 3-body charged-particle decays after implantation. Predicted α -cluster structures in 14 C were probed using resonant α scattering and the nature of the 3- α breakup of the 0 2 + Hoyle state in 12 C after the beta decay of 12 N and 12 B was studied. These experiments used in-flight radioactive-ion beams that were produced using the dual superconducting solenoid magnets TwinSol at the University of Notre Dame. Preliminary results from these experiments as well as the development of future radioactive beams to be used in conjunction with the PAT-TPC are presented.

The SPEDE spectrometer [1] aims to combine a silicon detector, for the detection of electrons, with the MINIBALL γ-ray detection array for in-beam studies employing radioactive ion beams at the HIE-ISOLDE facility at CERN. The setup will be primarily used for octupole collectivity [2] and shape coexistence studies [3, 4] in Coulomb excitation experiments. In the shape coexistence cases the transitions between states of the same spin and parity have enhanced E0 strength [5]. Additionally the 0→0 transitions, typically present in nuclei exhibiting shape coexistence [6], can only occur via E0 transitions, i.e. via internal conversion electron emission.

In-situ purification of the gas used as stopping medium in a noble gas ion catcher by operating the device at low temperatures of 60 to 150 K was investigated. Alpha-decay recoil ions from a 223Ra source served as energetic probes. The combined ion survival and transport efficiencies for 219Rn ions saturated below about 90 K, reaching 28.7(17) % in helium, 22.1(13) % in neon, and 17.0(10) % in argon. These values may well reflect the charge exchange and stripping cross sections during the slowing down of the ions, and thus represent a fundamental upper limit for the efficiency of noble gas ion catcher devices. We suggest the cryogenic noble gas ion catcher as a technically simpler alternative to the ultra-high purity noble gas ion catcher operating at room temperature., Comment: Submitted to Nucl. Instrum. Meth. Phys. Res. A

Initial measurements are presented of the (d,p) reactions on neutron-rich N = 50 isotones along the r-process path of nucleosynthesis with radioactive ion beams of 82Ge and 84Se. Prospects for measurements with unstable 130,132Sn beams are discussed.

Proton elastic scattering, proton inelastic scattering, proton transfer reactions and the (d, p) neutron transfer reaction have been measured in inverse kinematics with radioactive ion beams at the HRIBF to determine the properties of nuclear excited states that are important in stellar explosions. The experimental techniques and some initial results are briefly summarized.

Neutron-rich radioactive ion beams available from the HRIBF allow a variety of measurements around the 132Sn region, including Coulomb excitation and single-nucleon transfer. The B(E2;0+ → 2+) values for first 2+ excited states of even-even neutron-rich 132-136Te and 126-130Sn have been measured by Coulomb excitation in inverse kinematics. Neutron transfer onto a 134Te beam from 9Be and 13C targets, to populate single-particle states in 135Te, has also been studied. Gamma rays from the 13C(134Te, 12C) reaction were used to identify the νi13/2 state in 135Te, at an energy of 2109 keV. These and other results, and plans for future experiments with these neutron-rich beams, are presented.

An explosive hydrogen burning process occurring in novae or X-ray bursts has been suggested to be important for observation of 1.809-MeV gamma rays of 26 Al. In order to study relevant proton resonances in 26 Si and 27 P above the proton threshold, we performed elastic scattering experiments at low energies by using 25 Al and 26 Si radioactive ion beams. We investigated proton resonances in 26 Si up to E c.m. = 3.016 MeV as well as in 27 P up to E c.m. = 3.290 MeV. We compared observed proton resonances in 27 P with those obtained by the OXBASH shell model calculation.

The aim of the recoil separator ARES, installed at Louvain-la-Neuve, is to study (p, γ ) reactions of astrophysical interest involving unstable nuclei. ARES is coupled to CYCLONE44, a cyclotron dedicated to the post-acceleration of intense low-energy radioactive ion beams. The first measurement using a 19 Ne radioactive beam has been performed recently. The resonance strength of the state at 448 keV above the 19 Ne+p threshold has been investigated and an upper limit ω γ ⩽ 15.2 meV has been obtained. This first measurement with ARES has suggested some improvements to be performed to the separator, which are described in this paper.

As an effort to effectively use the short-lived radioactive ion beams to be available in near future at Tokai Radioactive Ion Accelerator Complex, we have developed a radiotracer method for diffusion studies in solids. A test experiment has been performed to measure the diffusion coefficients of Li in the sample of LiAl compound, by using the α-emitting radiotracer of 8Li (T1/2 = 0.84 s). The yields of α-particles emitted from diffusing 8Li primarily implanted in the sample have been measured as a function of time under a recurrent time sequence; the implantation of 8Li for 1.5 s (beam-on) and subsequent diffusion for 4.5 s (beam-off). We have found that the time-dependent yields of the α-particles could be used as a measure of the diffusivity of the tracer in a none-destructive way. By taking into account the experimental conditions, we have simulated the time-dependent α-particle yields for various diffusion coefficients and compared with the experimental ones in order to extract the diffusion coefficients of Li in the sample. The process of the simulations and the comparisons is discussed.

The measurements of nuclear moments have been conducted at RIKEN for the study of nuclei far from the β stability. Recent results for the magnetic moments of 30Al and 32Al obtained by means of β-NMR spectroscopy with spin-polarized radioactive beams from the projectile fragmentation reaction are presented. Remarks are also made on the developments and prospects for future moment studies at the RI Beam Factory.