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A non-destructive standard-free analytical method of obtaining stable isotope ratios in materials using nuclear reactions excited by an 11.75 MeV proton beam is demonstrated for a special 63Cu/65Cu target characterized traceably by Rutherford backscattering spectrometry (using 2.2 MeV protons). The method is general and is capable of being a useful alternative to standard ICP-MS methods. Relatively high energy proton beams are required to excite multiple isotopes of most elements of interest, and the many resulting nuclear reaction products are filtered by coincidence methods to characterize the desired isotope ratios. Specifically: the use of particle–gamma coincidences permits identification of specific channels populated in the nuclear reaction and avoids or minimizes typical drawbacks of this method including high backgrounds and interfering reactions. The test Cu target was a sandwich of a natural Cu and an enriched 65Cu foil, and particle–gamma coincidences were measured for the reactions 63Cu(p,πγ){63Cu,60Ni} and the corresponding reactions for 65Cu (where “π” represents the energetic charged particle reaction product: proton or alpha). Limitations of the method, and applications in cultural heritage and other fields are discussed.

The $^{8}\mathrm{Li}+^{58}\mathrm{Ni}$ collision is investigated at 23.9, 26.1, 28.7, and 30 MeV bombarding energies. Quasielastic angular distributions and the singles $^{7}\mathrm{Li}$ angular and energy distributions are presented. Coupled-reaction channels (CRC) calculations, which include the coupling of the elastic channel to $^{59}\mathrm{Ni}=^{58}\mathrm{Ni}\phantom{\rule{0.16em}{0ex}}+\phantom{\rule{0.16em}{0ex}}n$ states above and below the neutron threshold, provide a simultaneous description of the quasielastic and transfer distributions and evidence the strong effect of the one-neutron transfer/breakup channels on the quasielastic scattering. The $^{7}\mathrm{Li}$ angular and energy distributions have been also successfully analyzed combining the continuum discretized coupled channels (CDCC) method, for the elastic breakup, and the IAV model of Ichimura, Austern, and Vincent [Phys. Rev. C 32, 431 (1985)], for the nonelastic breakup. These calculations indicate that most of the $^{7}\mathrm{Li}$ yields are due to nonelastic breakup contributions (transfer), whereas elastic breakup plays a minor role.

In this contribution, we report on effects due to the cluster configuration of boron isotopes, \(^8\)B, \(^{10}\)B, \(^{11}\)B and \(^{12}\)B, in the elastic scattering on \(^{58}\)Ni target at energies close to the Coulomb barrier. The results of coupled channel calculations, where the different configurations of the boron isotopes, \(^8\)B \(=\) \(^7\)Be\(+\)p, \(^{10}\)B \(=\) \(^6\)Li\(+\) \(\alpha \), \(^{11}\)B \(=\) \(^7\)Li\(+\) \(\alpha \) and \(^{12}\)B \(=\) \(^{11}\)B\(+\)n, have been attributed to different effects in the angular distributions for the elastic scattering process, are present.

Alpha particle energy distributions in the 6He+120Sn collision have been measured at 7 bombarding energies above the Coulomb barrier. A phenomenological analysis of the centroids of the experimental distributions was performed and compared with the expected alpha-particle energies from breakup and neutron transfer reactions. Q-optimum conditions were determined using the Brinks formula for the di-neutron transfer reaction. A comparison of the measured alpha-particle production cross-sections with Continuum Discretized Coupled Channels (CDCC) calculations for breakup is presented. Fundacao de Amparo `a Pesquisa no Estado de Sao Paulo 2013/22100-7, 2014/19666-1 Conselho Nacional de Desenvolvimento Cientıfico e Tecnologico 308935/2018-7 Ministerio de Economía y Competitividad FIS2017-88410-P European Union 654002

Elastic scattering of a radioactive neutron-rich boron isotope, $^{12}\mathrm{B}$, has been measured for the first time. Angular distributions for the elastic scattering of $^{12}\mathrm{B}+^{58}\mathrm{Ni}$ have been measured at ${\mathit{E}}_{\mathrm{Lab}}=30.0$ and 33.0 MeV, which are just above the Coulomb barrier (${\mathit{V}}_{\mathrm{B}}=24$ MeV). The obtained angular distributions were analyzed in terms of the large-scale coupled channel (CC) and coupled reaction channel (CRC) calculations, where several inelastic transitions for the target, as well as the most relevant transfer reactions, have been included in the coupling matrix elements. The roles of the spin reorientation and spin-orbit interaction in the reaction mechanism were also investigated. The one-neutron transfer reaction through a coupled reaction calculation had some effect on the elastic scattering of the system studied.

A large yield of $\ensuremath{\alpha}$ particles produced in the $^{120}\mathrm{Sn}(^{6}\mathrm{He},\ensuremath{\alpha})$ reaction was measured at 20.3-, 22.2-, 22.4-, and 24.5-MeV bombarding energies. The $\ensuremath{\alpha}$ particles are distributed over a broad energy range in the vicinity and below the elastic scattering $^{6}\mathrm{He}$ peak. Energy integrated $\ensuremath{\alpha}$-particle cross sections have been obtained at ${\ensuremath{\theta}}_{\text{lab}}={36}^{\ensuremath{\circ}},{40}^{\ensuremath{\circ}}$, and ${60}^{\ensuremath{\circ}}$. The $\ensuremath{\alpha}$ energy distributions have been analyzed at a fixed laboratory angle $(\ensuremath{\approx}{60}^{\ensuremath{\circ}})$ in terms of the reaction $Q$ value, considering the $2n$-transfer reaction kinematics $^{120}\mathrm{Sn}(^{6}\mathrm{He},\ensuremath{\alpha})^{122}\mathrm{Sn}$. A kinematical analysis of the $Q$-value distribution shows that the recoil system $^{120}\mathrm{Sn}+2n$ is formed in highly excited states in the continuum, at increasing excitation energies as the bombarding energy increases. It is shown that by using Brink's formula, the excitation energy depends on the transferred angular momentum following a linear relation with the square of the angular momentum, indicating that some kind of dinuclear rotating system is formed after the reaction.

Experimental angular distributions for the $^{7}\mathrm{Li}\phantom{\rule{0.16em}{0ex}}+\phantom{\rule{0.16em}{0ex}}^{120}\mathrm{Sn}$ elastic and inelastic (projectile and target excitations) scattering, and for the neutron stripping reaction, have been obtained at ${E}_{\mathrm{LAB}}=20$, 22, 24, and 26 MeV, covering an energy range around the Coulomb barrier $({V}_{B}^{(\mathrm{LAB})}\ensuremath{\approx}21.4$ MeV). Coupled channel and coupled reaction channel calculations were performed and both describe satisfactorily the experimental data sets. The ${\frac{1}{2}}^{\ensuremath{-}}$ state $^{7}\mathrm{Li}$ inelastic excitation (using a rotational model), as well as the projectile coupling to the continuum $(\ensuremath{\alpha}$ plus a tritium particle) play a fundamental role on the proper description of elastic, inelastic, and transfer channels. Couplings to the one-neutron stripping channel do not significantly affect the theoretical elastic scattering angular distributions. The spectroscopic amplitudes of the transfer channel were obtained through a shell model calculation. The theoretical angular distributions for the one-neutron stripping reaction agreed with the experimental data.

An overview of the experiments performed at RIBRAS over the last year is presented. Elastic scattering and breakup reactions induced by light exotic projectiles on different targets have been measured and some results are presented here for the 120Sn(6He, α) reaction. Resonant scattering experiments have been performed with 10Be and 12C secondary beams on a CH2 thick target and the well known 12C+p resonance was identified. A gamma-particle experiment using a new system of LYSO scintillators to detect gammas was done.

In this work we present an elastic scattering angular distribution for the 8Li+58Ni system measured at Elab = 26.1 MeV. The 8Li beam was produced in the Radioactive Ion Beams in Brasil (RIBRAS) facility using the 7Li primary beam delivered by the 8-UD Pelletron accelerator. The angular distribution covers the angular range from 20 to 85 degrees in the center of mass frame. The data have been analysed by optical model and coupled channels calculations, including couplings to low-lying states in 8Li and the spin-orbit interaction. Our results indicate that the inclusion of the spin-orbit interaction in the calculations is important to describe the data at backward angles.

The experiment was performed at the GSI facility in Darmstadt (Germany).; Around 270 medium-mass residual nuclei, formed in spallation reactions induced by 136Xe projectiles impinging on a liquid hydrogen target at 500 AMeV, have been unambiguously identified at GSI using the magnetic spectrometer FRS. The individual production cross sections and the longitudinal momentum distributions have been determined with high accuracy. These data represent an important constraint for theoretical models describing spallation reactions.

Residual fragment production in reactions induced by $^{136}\mathrm{Xe}$ projectiles impinging on a liquid deuterium target at $500A$ MeV has been measured at GSI. Projectile residues were unambiguously identified in atomic and mass numbers using the Fragment Separator as high-resolution zero-degree spectrometer. The isotopic production yields of these residuals were used to benchmark reference model calculations describing spallation reactions. In particular the energy dissipated in these reactions was assessed by comparing the production yields measured in this work with the ones obtained in reactions induced by $^{136}\mathrm{Xe}$ projectiles on protons at $1000A$ and $500A$ MeV.

The odd-odd 58 Co nucleus has been studied with the 51 V( 10 B, p2n) reaction at 33 MeV and 36 MeV incident energy using the γ-spectrometer Saci-Perere. Excited states up to 8.0 MeV and spin up to 11 + have been observed. DSAM lifetimes for 13 excited states were measured. The results are compared to shell model calculations using the GXPF1 effective interaction, developed for use in the fp shell.

Two nuclear reactions, 11B+100Mo, (Eb=43 MeV) and 16O+51V, (Eb=70 MeV) were studied with a g spectrometer with a charged particle array in order to measure the correlation between g-rays emitted by residual nuclei produced by heavy-ion reactions in coincidence with a charged particles detected at different angles. Ratios of g-transition intensities in coincidence with charged particles were measured for the main products of these reactions, providing a differentiation between the exit channels, even when complete fusion is the only reaction mechanism.

Energy loss measurements for the slowing down of Ag ions in Au, in the velocity range 1:6v0 < v < 4:4v0, where v0 is the Bohr velocity, are presented. The measurements were performed using the Doppler shift technique and also with a new method, where a secondary beam of low velocity heavy ions is produced by elastic scattering of the accelerated beam. The results are compared to the SRIM2000 calculations (www.srim.org) and to recent measurements in this velocity region.

A large solid angle low-Z charged particle detector system was built in order to improve the quality of the identification and selection of evaporation channels for in-beam γ-spectroscopy measurements. The array consists of 11 plastic phoswich telescopes closely packed in a 4π arrangement and to be used as an ancillary system for the Pelletron Laboratory γ-ray spectrometer. The new system was tested in γ-particle and γ–γ-particle coincidence measurements using the 27 Al + 16 O and 100 Mo + 11 B reactions, at 53 and 43 MeV incident beam energies, respectively. The values for the particle detection efficiency and improvement in the peak to background ratios are considered acceptable for the usefulness of the system.

Measurements of the p({sup 6}He,p) elastic scattering excitation function have been performed in the RIBRAS system using a {sup 6}He secondary beam and a CH{sub 2} polyethylene thick target. The motivation is to observe states of the compound nucleus {sup 7}Li in the excitation energy range of E{sub exc}{sup 7Li} = 10.8-11.8MeV, where the isobaric analog state of {sup 7}He ground state lies. Excitation functions have been obtained at three laboratory angles θ{sub lab} = 0°, 20°, and 25° which correspond to θ{sub c.m} = 180°, 140°, and 130°.

The 105Rh nucleus has been studied by in-beam g spectroscopy with the heavy-ion fusion-evaporation reaction 100Mo(11B, 02ng) at 43 MeV. A rich variety of structures was observed at high and low spin, using g - g - t and g - g - particle coincidences and directional correlation ratios. Four magnetic dipole bands have also been observed at high spin. Two of them are nearly degenerate in excitation energy and could be chiral partners, as predicted by Tilted Axis Cranking calculations.

The 108 Pd nucleus has been studied with the 100 Mo( 11 B, p2nγ) reaction at 43 MeV incident energy. γ − γ − t, γ −γ− charged particle coincidences and directional correlation ratios were measured using the γ spectrometer formed by four Compton suppressed HPGe detectors and a4π charged-particle ancillary detector system. The struture of the bands was interpreted within the framework of the cranked shell model and total Routhian calculations.

The reaction of 7Li+120Sn has been measured at bombarding energies of 21, 24 and 27 MeV. The -ray transition in 120Sn was observed and the angular distribution for the 2+ excited state was obtained. Coupled channels and coupled-reaction channels calculations, including the dynamical polarization potential due to the projectile break-up, obtained from continuum discretized coupled channel calculations, were performed. The comparison between the existing experimental elastic angular distribution with the coupled-reaction channels calculations indicates that the 1n stripping transfer is the most intense channel to be coupled and the 2n stripping reaction occurs sequentially rather than directly, however, further data must be analyzed to confirm this indication. The experimental elastic and inelastic scattering data were well described by the calculations, but some discrepancies in these channels may indicate the need for corrections to the nuclear potential and/or the necessity to incorporate further channels.

The production of radioactive ions using the Isotope Separation On-Line method gives rise, in most cases, to singly charged ions. In order to perform experiments with postaccelerated radioactive ion beams, these ions have to be multicharged. We describe here a new compact design for a charge breeder that will be coupled to the production target of SPIRAL1 at GANIL. We present recent results obtained offline with stable alkali ions (Na, K, Rb, and Cs) on the SIRa test bench. Particularly, 1(+) to N(+) conversion efficiencies and conversion times are presented. Several points have been identified for the improvements of the present performances.

The root-mean-square (rms) nuclear charge radius of $^{8}\mathrm{He}$, the most neutron-rich of all particle-stable nuclei, has been determined for the first time to be 1.93(3) fm. In addition, the rms charge radius of $^{6}\mathrm{He}$ was measured to be 2.068(11) fm, in excellent agreement with a previous result. The significant reduction in charge radius from $^{6}\mathrm{He}$ to $^{8}\mathrm{He}$ is an indication of the change in the correlations of the excess neutrons and is consistent with the $^{8}\mathrm{He}$ neutron halo structure. The experiment was based on laser spectroscopy of individual helium atoms cooled and confined in a magneto-optical trap. Charge radii were extracted from the measured isotope shifts with the help of precision atomic theory calculations.

International audience; In the framework of the production of radioactive alkali ion beams by the isotope separator on-line (ISOL) method in SPIRAL, a surface ionization source has been developed at GANIL to produce singly-charged ions of Li, Na and K. This new source has been designed to work in the hostile environment found at SPIRAL whilst having a long lifetime. This new system of production has two ohmic heating components: the first for the target oven and the second for the ionizer. The latter, being in carbon, offers high reliability and competitive ionisation efficiency. This new surface ionization source has been tested on line using a 48Ca primary beam at 60,3A MeV with an intensity of 0,14 pµA. The ionization efficiencies obtained for Li, Na and K are significantly better than the theoretical values calculated using the known Langmuir surface ionisation equation. Moreover, the design of the ion source avoids the cavity effects reported by Kirchner. The enhanced efficiency can be understood by considering a particular effect related to the polarization of the ionizer. This feature is shown to be extremely important also for short-lived isotopes. In the future, this source will be associated with the multicharged electron-cyclotron-resonance (ECR) ion source NANOGAN III for production of multicharged alkali ions in SPIRAL. The preliminary tests of the setup for the production of multicharged alkali ions will also be presented in this contribution.

In earlier works, the fusion cross section for the 16O+16O reaction has been measured using different techniques. In the present work, we have obtained an experimental excitation function for 16O+16O using γ-ray spectroscopy. The measurements were performed at center-of-mass energies between 8.28 and 12.25 MeV. The theoretical predictions obtained with a coupled-channel model are consistent with the experimental data. From our analyses, the extrapolated S-factor value at 6.6 MeV, corresponding to the Gamow peak energy for core oxygen burning conditions, is about 3.6 × 1025 MeV barn.

High-spin states in the odd-odd $^{58}\mathrm{Co}$ nucleus have been studied with the fusion-evaporation reaction $^{51}\mathrm{V}$ ($^{10}\mathrm{B}$,$p2n$) using the \ensuremath{\gamma}-spectrometer Saci-Perere. Thirty-six new excited states up to spin ${11}^{+}$ and an excitation energy of 8.0 MeV have been observed, which are connected by 46 \ensuremath{\gamma}-ray transitions. Transition probabilities for 14 excited states were measured through the Doppler-shift attenuation method. The results are compared with shell-model calculations using the GXPF1 effective interaction, developed for use in the pf shell. These results were interpreted by considering particle-hole excitations with respect to the doubly magic $N=Z=28$ core.

High-spin states in the neutron-deficient140Gd nucleus have been studied with the 92Mo(54Fe,alpha2p) reaction at a beam energy of 240 MeV. The level scheme of 140Gd was considerably extended from what was previously known. In this work we concentrate on one of the 9 bands observed, which presents relatively strong M1 transitions and negligible signature splitting, and has an isomeric band-head, indicating a strongly coupled or high-K configuration. We compare this band to the Kpi = 8- bands observed in N=74 isotones and propose a similar configuration assignment, but with a somewhat larger deformation.

The $^{105}\mathrm{Rh}$ nucleus has been studied with the $^{100}\mathrm{Mo}(^{11}\mathrm{B},\ensuremath{\alpha}2n\ensuremath{\gamma})$ reaction at $43\phantom{\rule{0.3em}{0ex}}\text{MeV}$ incident energy. A rich variety of structures was observed at high and low spins, using $\ensuremath{\gamma}\text{\ensuremath{-}}\ensuremath{\gamma}\text{\ensuremath{-}}t$ and $\ensuremath{\gamma}\text{\ensuremath{-}}\ensuremath{\gamma}\text{\ensuremath{-}}\mathit{particle}$ coincidences and directional correlation ratios. A $\ensuremath{\gamma}$-vibrational band was observed for the first time in this nucleus. A new structure based on the intruder $1∕{2}^{+}$[431] proton orbital was identified. Four magnetic dipole bands have also been observed at high spin, three of which have negative parity and have similar characteristics: they are very regular in energy spacing, presenting nearly constant alignments and large values of $B(M1)∕B(E2)$ ratios. Two of them are nearly degenerate in excitation energy and could be chiral partners. The $\ensuremath{\pi}{g}_{9∕2}\ensuremath{\bigotimes}\ensuremath{\nu}{h}_{11∕2}({g}_{7∕2},{d}_{5∕2})$ configuration is tentatively assigned for these bands, with the angular momenta of the proton and neutron intruders and the collective angular momentum aligning along the three perpendicular axes of the triaxial core, as predicted by tilted axis cranking calculations.

A recent experiment has been performed in the double solenoid system Radioactive Ion Beams in Brasil (RIBRAS) by impinging a pure 6 He secondary beam on a thick CH 2 target to measure the 6 He + p excitation function. Results of this experiment will be presented.

International audience; More than 600 residual nuclei, formed in the spallation of 136Xe projectiles impinging on deuterium at 500AMeV of incident energy, have been unambiguously identified and their production cross sections have been determined with high accuracy. By comparing these data to others previously measured for the reactions 136Xe + p at 1AGeV and 136Xe + p at 500AMeV we investigated the role that neutrons play in peripheral collisions and to understand the energy dissipation in frontal collisions in spallation