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The NSCL has successfully used linear gas stopping cells for more than a decade to slow down near-relativistic projectile fragments to energies of tens of keV; first for experiments at low energy and later for reacceleration to Coulomb-barrier energies. In order to stop and rapidly extract light and medium-mass fast ions, which are difficult to efficiently thermalize in linear gas cells, a gas-filled, reverse cyclotron has been constructed. The device uses a cyclotron-type magnet and helium gas in a liquid-nitrogen (LN) cooled stopping chamber to confine and slow down the injected beam. The stopped ions are transported to the center of the magnet by an RF-carpet system, extracted axially through the bore with an ion conveyor and accelerated to For magnet commissioning and low-energy ion tests, the cyclotron gas stopper was constructed in a location that did not allow connection to the NSCL high-energy beamlines. However, all other components have been installed for the device. Efficient ion transport has been demonstrated with ions from a movable alkali source with the magnet energized. An experimental vault is being prepared to allow the connection of the cyclotron gas stopper to the NSCL beamline. The design for a dedicated momentum-compression beam line, similar to the ones feeding the existing linear gas cells [1] , [2] , is complete and the components are under construction. Offline tests have ended and moving the cyclotron stopper to its destination has begun.

Thermalization of fast ions in a buffer gas provides a method to transform the high-energy, exotic beams produced by projectile fragmentation at the National Superconducting Cyclotron Laboratory (NSCL) into low-energy beams. The process includes slowing down the fast exotic beams in solid degraders combined with momentum compression and removal of the remaining kinetic energy by collisions with a buffer gas. The original beam thermalization area for mass measurements at the NSCL was reconfigured to accommodate a new momentum compression beam line, a large radio-frequency (RF) gas catcher constructed by Argonne National Lab and a low-energy beam transport system. A large variety of exotic isotopes produced by projectile fragmentation and selected by the A1900 fragment separator was thermalized in the 1.2 m long gas catcher filled with helium at approximately 100 mbar. The ions were guided to an extraction nozzle with a combination of electrostatic and RF potentials and ejected by the gas flow. A novel RF ion guide was used in a differential pumping system to remove the helium and transport the ions into ultrahigh vacuum. Finally, the ions were accelerated to 30 kV for transport to various experiments. The distribution of the thermalized ions among chemical adducts is one of the operational challenges. The important steps implemented to minimize the production of the chemical adducts in the gas catcher are discussed. The operational status of the facility and some example results from characterization of the gas catcher operation with 37 K and 47 K beams are presented.

Linear gas stoppers filled with helium have become a common tool to convert high energy rare isotope beams into low-energy beams. The National Superconducting Cyclotron Laboratory (NSCL) has designed and fabricated a new cryogenic gas stopper to maximize efficiency and beam rate capability in order to increase scientific reach at the facility. The Advanced Cryogenic Gas Stopper (ACGS) will increase extraction efficiency, reduce transport time, reduce molecular contamination of the isotope of interest, and minimize space charge effects. A novel 4-phase Radio Frequency wire-carpet generates a traveling electrical wave for fast ion transport, cryogenic cooling of the helium gas chamber reduces unwanted molecular formation, and the new planar geometry with the wire-carpet in the mid-plane of stopper alleviates space charge effects. Prototype testing of ACGS components have shown wire-carpet transport efficiencies greater than 95% and transport speeds up to 100 m/s. This presentation will show the first online tests with radioactive beams and report the efficiencies of the ACGS.

The Re-Accelerator (ReA3) facility at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU) delivers rare isotope and stable beams ranging from 0.3 MeV/u to 6 MeV/u to experimental end stations. The High Energy Beam Transport (HEBT) line into the ReA3 experimental hall houses several quadrupole magnets, dipole magnets, and combined function horizontal and vertical corrector magnets. All of these are iron-dominated, resistive type magnets. This paper describes the magnetic performance of 45°dipole magnets installed in both the vertical and horizontal section of the ReA3 beamline. The computed field map and the derived data provide a reference for the operational setting of the magnet and input for the beam optics study. The field measured by both Hall and NMR probes agrees well with the calculations suggesting that the magnet performance meets the design specification.

Linear gas stoppers are widely used to convert high-energy, rare-isotope beams and reaction products into low-energy beams with small transverse emittance and energy spread. Stopping of the high-energy ions is achieved through interaction with a buffer gas, typically helium, generating large quantities of He + /e − pairs. The Advanced Cryogenic Gas Stopper (ACGS) was designed for fast, efficient stopping and extraction of high-intensity, rare-isotope beams. As part of the design process, a comprehensive particle-in-cell code was developed to optimize the transport and extraction of rare isotopes from the ACGS in the presence of space charge, including He + /e − dynamics, buffer gas interactions including gas flow, radio-frequency carpets, and ion extraction through a nozzle or orifice. Details of the simulations are presented together with comparison to experiment when available.

We have developed and tested an experimental technique for the measurement of low-energy (p,n) reactions in inverse kinematics relevant to nuclear astrophysics. The proposed setup is located at the ReA3 facility at the National Superconducting Cyclotron Laboratory. In the current approach, we operate the beam-transport line in ReA3 as a recoil separator while tagging the outgoing neutrons from the (p,n) reactions with the low-energy neutron detector array (LENDA). The developed technique was verified by using the $^{40}$Ar(p,n)$^{40}$K reaction as a probe. The results of the proof-of-principle experiment with the $^{40}$Ar beam show that cross-section measurements within an uncertainty of $\sim$25\% are feasible with count rates up to 7 counts/mb/pnA/s. In this article, we give a detailed description of the experimental setup, and present the analysis method and results from the test experiment. Future plans on using the technique in experiments with the separator for capture reactions (SECAR) that is currently being commissioned are also discussed., Comment: Submitted to NIMA. Revised manuscript after referees' first review

The project ICH15 aims for the design of a heavy-ion facility capable of accelerating protons up to an energy of 70 MeV and 5 MeV/u heavy-ions with A/Q \(=\) 3. The objective is to simultaneously produce radioisotopes and deliver a low energy proton beam for cancer therapy (uveal tumour). In this contribution we present an overview of the project, including a selection of medical-physics goals and technical developments: beam dynamics calculation, electromagnetic and thermo-mechanical analysis, the control system and the irradiation facilities. Studies have been carried put with Comsol Multiphysics (Comsol multiphysics 5.3. http://www.comsol.com/products/multiphysics/ [1]) and Global Tracer Particle (General particle tracer. http://www.pulsar.nl/gpt/ [2]).

In radioactive ion beam experiments, beams containing isomers can be of interest in probing nuclear structure and informing astrophysical reaction rates. While the production of mixed in-flight ground state and isomer beams using nucleon transfer can be generally understood through distorted wave Born approximation methodology, low-spin isomer production via fast fragmentation is relatively unstudied. To attain a practical understanding of low-spin isomer production using fast fragmentation beams, a test case of $^{38}\mathrm{K}/^{38m}\mathrm{K}$ was studied at the National Superconducting Cyclotron Laboratory's ReAccelerated Beam facility. Starting from lise++ predictions, the fragmentation momentum distribution was sampled to determine isomer production. In addition, the effects of the gas stopper gradient and charge breeding times were examined. In the case of $^{38}\mathrm{K}$, isomer production peaks at $\ensuremath{\sim}57%$. This maximum is observed just off the lise++ predicted optimum magnetic rigidity, with only small losses in beam intensity within a few percent of this optimum rigidity setting. Control of the isomer fraction was also achieved through the modification of charge breeding times. Fast fragmentation appears to be a feasible method for production of low-spin isomeric beams, but additional study is necessary to better describe the mechanism involved.

Linear gas stopping cells have been used successfully at NSCL to slow down ions produced by projectile fragmentation from the 100 MeV/u to the keV energy range. These ‘stopped beams’ have first been used for low-energy high precision experiments and more recently for NSCLs re-accelerator ReA. A gas-filled reverse cyclotron is currently under construction by the NSCL to complement the existing stopping cells: Due to its extended stopping length, efficient stopping and fast extraction is expected even for light and medium-mass ions, which are difficult to thermalize in linear gas cells. The device is based on a 2.6 T maximum-field cyclotron-type magnet to confine the injected beam while it is slowed down in ≈100 mbar of LN2-temperature helium gas. Once thermalized, the beam will be transported to the center of the device by a traveling-wave RF-carpet system, extracted along the symmetry axis with an ion conveyor and miniature RF-carpets, and accelerated to a few tens of keV of energy for delivery to the users. The superconducting magnet has been constructed on a 60 kV platform and energized to its nominal field strength. The magnet’s two cryostats use 3 cryo-refrigerators each and liquid-nitrogen cooled thermal shields to cool the coil pair to superconductivity. This concept, chosen not to have to rely on external liquid helium, has been working well. Measurements of axial and radial field profiles confirm the field calculations. The individual RF-ion guiding components for low-energy ion transport through the device have been tested successfully. The beam stopping chamber with its 0.9 m-diameter RF carpet system and the ion extraction system are being prepared for installation inside the magnet for low-energy ion transport tests.

Use of a beam-based approach is presented for establishing a rigidity calibration for the A1900 fragment separator located at the National Superconducting Cyclotron Laboratory. Also presented is why an alternative approach to the rigidity calibration – using detailed field maps of individual magnetic components – is not a feasible basis for deriving an accurate calibration. The level of accuracy achieved for the rigidity calibration is ±0.1%.

International audience; We discuss the motivation and technique of Penning trap mass spectrometry applied to radioactive$^{44}$V and$^{44}^{m}$V, using the LEBIT 9.4 T Penning trap mass spectrometer at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University. A complementary measurement of these nuclides, performed at the CSRe in Lanzhou, China, was recently published, but with errors several times larger than obtainable for a short-lived radionuclide in a Penning trap. Interpretation of the higher precision results is ongoing and a full accounting of this measurement is anticipated in the coming months.

The electron-beam ion trap (EBIT) charge breeder of the ReA post-accelerator, located at the National Superconducting Cyclotron Laboratory (Michigan State University), started on-line operation in September 2015. Since then, the EBIT has delivered many pilot beams of stable isotopes and several rare-isotope beams. An operating aspect of the ReA EBIT is the breeding of high charge states to reach high reaccelerated beam energies. Efficiencies in single charge states of more than 20% were measured with ${^{39}\mathrm{K}}^{15+}$, ${^{85}\mathrm{Rb}}^{27+}$, ${^{47}\mathrm{K}}^{17+}$, and ${^{34}\mathrm{Ar}}^{15+}$. Producing high charge states demands long breeding times. This reduces the ejection frequency and, hence, increases the number of ions ejected per pulse. Another operating aspect is the ability to spread the distribution in time of the ejected ion pulses to lower the instantaneous rate delivered to experiments. Pulse widths were stretched from a natural $25\text{ }\text{ }\ensuremath{\mu}\mathrm{s}$ up to $\ensuremath{\sim}70\text{ }\text{ }\mathrm{ms}$. This publication reviews the progress of the ReA EBIT system over the years and presents the results of charge-breeding efficiency measurements and pulse-stretching tests obtained with stable- and rare-isotope beams. Studies performed with high sensitivity to identify and quantify stable-isotope contaminants from the EBIT are also presented, along with a novel method for purifying beams.

The region near Z=28, N=40 is a subject of great interest for nuclear structure studies due to spectroscopic signatures in $^{68}$Ni suggesting a subshell closure at N=40. Trends in nuclear masses and their derivatives provide a complementary approach to shell structure investigations via separation energies. Penning trap mass spectrometry has provided precise measurements for a number of nuclei in this region, however a complete picture of the mass surfaces has so far been limited by the large uncertainty remaining for nuclei with N > 40 along the iron and cobalt chains. Here we present the first Penning trap measurements of $^{68,69}$Co, performed at the Low-Energy Beam and Ion Trap facility at the National Superconducting Cyclotron Laboratory. In addition, we perform ab initio calculations of ground state and two-neutron separation energies of cobalt isotopes with the valence-space in-medium similarity renormalization group approach based on a particular set of two- and three-nucleon forces which predict saturation in infinite matter. We discuss the importance of these measurements and calculations for understanding the evolution of nuclear structure near $^{68}$Ni., 7 pages, 6 figures

The systematic study of fission fragment yields under different initial conditions has provided valuable experimental data for benchmarking models of fission product yields. Nuclear reactions using inverse kinematics coupled to the use of a high-resolution spectrometer with good fragment identification are shown here to be a powerful tool to measure the inclusive isotopic yields of fission fragments. In-flight fusion-fission was used in this work to produce secondary beams of neutron-rich isotopes in the collisions of a 238U beam at 24 MeV/u with 9Be and 12C targets at GANIL using the LISE3 fragment separator. Unique identification of the A, Z, and atomic charge state, q, of fission products was attained with the $\Delta E$ -TKE-B $\rho$ -ToF measurement technique. Mass, and atomic number distributions are reported for the two reactions. The results show the importance of different reaction mechanisms in the two cases. The optimal target material for higher yields of neutron-rich high-Z isotopes produced in fusion-fission reactions as a function of projectile energy is discussed.

The systematic study of fission fragment yields under different initial conditions provides a valuable experimental benchmark for fission models that aim to understand this complex decay channel and to predict reaction product yields. Inverse kinematics coupled to the use of a high-resolution spectrometer is shown to be a powerful tool to identify and measure the inclusive isotopic yields of fission fragments. In-flight fusion fission was used to produce secondary beams of neutron-rich isotopes in the collision of a 238U beam at 24 MeV/u with 9Be and 12C targets at GANIL using the LISE3 fragment-separator. Unique A,Z,q identification of fission products was attained with the dE-TKE-Brho-ToF measurement technique. Mass, and atomic number distributions are reported for the two reactions that show the importance of different reaction mechanisms for these two targets., Comment: 14 pages, 10 figures, 4 tables

Presented at the XXXIV Mazurian Lakes Conference on Physics, Piaski, Poland, September 6–13, 2015, During the last years, the ECOS working group has been considering the construction of a new high-intensity accelerator of stable ion beams for the next Long-Range Plan of the nuclear physics community in Europe. The new facility (LINCE) will be a multi-user facility dedicated to ECOS science: fundamental physics, astrophysics, nuclear structure and reaction dynamics. In this paper, we summarize preliminary design studies of the low-energy part of this facility based on the use of a multi-ion supercon- ducting linac., Work partially supported by the Spanish Government under the grant Feder-Interconnecta “Aceltec” ITC-20111070. The authors are also grateful to the companies Alter Technology-Tüv, Avs, Cibernos, Elitt Energy, Faysol, Idom, and Tti Norte for partial funding of this work and active participation in the design and prototyping carried-out in this study.

Presented at the XXXIV Mazurian Lakes Conference on Physics, Piaski, Poland, September 6–13, 2015., The ECOS is considering the construction of a new facility for accelerating high intensity stable beams with energies at and above the Coulomb barrier, the LINCE light and heavy ion accelerator. This facility could be based on a normal conducting CW-RFQ and a superconducting linac, working at 72.75 MHz. This paper presents a design study for the RFQ system which is able to achieve 500 keV/u output for A=Q = 7 ions in only 5 m length.

ECOS-LINCE (Martel I et al., Proceedings IPAC’14, 2014) is a proposal for a new European First Class high intensity heavy-ions accelerator for stable ions, with energies at and above the coulomb barrier. The low energy section will be achieved using a 72.75 MHz normal conducting four vanes RFQ designed to give a 460 keV/u boost for A/Q = 7 ions in about 5 m (Orduz AK et al., IPAC’14, 2014). The geometry vanes are modeled to accommodate windows in order to obtain a clear separation of the RFQ modes (Ostroumov P et al., Rev ST Accel Beams 15:110101, 2012). This article presents the experimental results of the RF test carried out on a aluminum prototype.

International audience; Pioneering in-flight fission experiments at GSI intensively explored neutron-rich isotopes with Z=28-60. Elements with Z > 60 were weakly produced in these experiments. The alternative technique to produce these nuclei, fusion-fission reactions with heavy targets in normal kinematics, suffers from difficulties with fragment extraction from the target and their identification. In-flight fusion-fission could be a useful production method to enable a large number of experiments aimed to identify new neutron-rich isotopes and study their properties. In particular, the study of the beta decay properties of fission products and their lifetimes is of central importance to numerous applications in nuclear physics and related disciplines, such as astrophysics, particle physics and nuclear engineering. A fast analytical Fusion-Fission model has been developed in the LISE++ framework to estimate the expected yields in in-flight fusion-fission experiments.

International audience; The Super Separator Spectrometer (S3) is a device to be designed for experiments with the very high intensity stable beams of LINAG, the superconducting linear accelerator of GANIL, which will be built in the framework of SPIRAL2. These beams, which will provide in a first phase of SPIRAL2 ions with A/q = 3, can reach intensities exceeding 100 pµA for lighter ones - A

International audience; The first accelerated exotic beam of the SPIRAL (Production System of Radioactive Ion and Acceleration On-Line) facility at GANIL at Caen has been delivered for experiments in September 2001. After working for almost 5 years, 32 experiments were performed in the facility using exotic isotopes of helium, oxygen, neon, argon and krypton. The intensities of the radioactive beams increased since the first beam was delivered. Nominal intensity values are achieved for most of noble gas beams. Developments of new beams as well as the increasing of present intensities for a number of isotopes are being undertaken. In particular, in this contribution it is presented the first results obtained for the production of light alkali beams. Other developments are also envisaged in the close future.

We report the first direct measurement of the $^{14}\mathrm{O}$ superallowed Fermi $\ensuremath{\beta}$-decay ${Q}_{EC}$ value, the last of the so-called ``traditional nine'' superallowed Fermi $\ensuremath{\beta}$ decays to be measured with Penning trap mass spectrometry. $^{14}\mathrm{O}$, along with the other low-$Z$ superallowed $\ensuremath{\beta}$ emitter, $^{10}\mathrm{C}$, is crucial for setting limits on the existence of possible scalar currents. The new ground state ${Q}_{EC}$ value, 5144.364(25) keV, when combined with the energy of the ${0}^{+}$ daughter state, ${E}_{x}({0}^{+})=2312.798(11)\text{ }\text{ }\mathrm{keV}$ [, Nucl. Phys. A523, 1 (1991)], provides a new determination of the superallowed $\ensuremath{\beta}$-decay ${Q}_{EC}$ value, ${Q}_{EC}(\mathrm{sa})=2831.566(28)\text{ }\text{ }\mathrm{keV}$, with an order of magnitude improvement in precision, and a similar improvement to the calculated statistical rate function $f$. This is used to calculate an improved $\mathcal{F}t$ value of 3073.8(2.8) s.

The Low Energy Beam and Ion Trap (LEBIT) Penning trap mass spectrometer was used to perform an improved-precision mass measurement of $^{72}\mathrm{Br}$ and the low-lying isomeric state, $^{72m}\mathrm{Br},$ giving mass excesses of $\ensuremath{-}59\phantom{\rule{0.16em}{0ex}}062.2(1.0)\phantom{\rule{0.16em}{0ex}}\mathrm{keV}$ and $\ensuremath{-}58\phantom{\rule{0.16em}{0ex}}960.9(1.2)\phantom{\rule{0.16em}{0ex}}\mathrm{keV}$, respectively. These values are consistent with the values from the 2012 atomic mass evaluation [Chin. Phys. C 36, 1603 (2012)] and the Nubase2012 evaluation of nuclear properties [Chin. Phys. C 36, 1157 (2012)]. The uncertainties on the mass of the ground state and isomeric state have been reduced by a factor of seven.

The first accelerated exotic beam of the Production System of Radioactive Ion and Acceleration On-Line (SPIRAL) facility at Grand Accelerateur National d’Ions Lourds, Caen has been delivered for the first experiment in the end of September 2001. The 18Ne (half-live of 1.67 s) isotope has been produced through the projectile fragmentation of a 20Ne primary beam at 95A MeV on a carbon target, located at the new underground production cave of SPIRAL. For this first experiment, a maximum primary beam intensity of 0.18 pμA was used, in order to limit the irradiation of the production ensemble. The radioactive atoms released from the carbon target – heated at 1800 °C – were ionised by the compact and totally permanent magnet Nanogan-3 electron cyclotron resonance ion source to the charge state 4+. The beam was accelerated by the new compact cyclotron for medium energy ions up to the energy of 7A MeV. The maximum beam intensity of 18Ne achieved during this first run was of 2×106 particles per second at the experimental area. The beam was contaminated by 15% of 18O and a very small amount (

The accelerated ISOL technique is presented as an introduction to the present status of the SPIRAL facility. SPIRAL is based on the very high intensity light and heavy-ion beams available at GANIL. The facility will deliver radioactive beams with energies in the range between 1.7 and 25 A MeV. The current state of target-ion source production system, as well as the new developments undertaken by the target ion-source group at GANIL are presented.

Expérience GANIL/VAMOS/LISE; International audience; Two fission experiments have been performed at GANIL using 238U beams at different energies and light targets. Different fissioning systems were produced with centre of mass energies from 10 to 240MeV and their decay by fission was investigated with GANIL spectrometers. Fission-fragment isotopic distributions have been obtained. The evolution with impinging energy of their properties, the neutron excess and the width of the neutron-number distributions, gives important insights into the dynamics of the fusionfission mechanism.

We report on direct time-of-flight based mass measurements of 16 light neutron-rich nuclei. These include the first determination of the masses of the Borromean drip-line nuclei (19)B, (22)C, and (29)F as well as that of (34)Na. In addition, the most precise determinations to date for (23)N and (31)Ne are reported. Coupled with recent interaction cross-section measurements, the present results support the occurrence of a two-neutron halo in (22)C, with a dominant ν2s(1/2)(2) configuration, and a single-neutron halo in (31)Ne with the valence neutron occupying predominantly the 2p(3/2) orbital. Despite a very low two-neutron separation energy the development of a halo in (19)B is hindered by the 1d(5/2)(2) character of the valence neutrons.

During the fission process, the nucleus deforms and elongates up to the two fragments inception and their final separation at scission deformation. The evolution of the nucleus energy with deformation is determined by the macroscopic properties of the nucleus, and is also strongly influenced by the single-particle structure of the nucleus. The fission fragment distribution is a direct consequence of the deformation path the nucleus has encountered, and therefore is the most genuine experimental observation of the potential energy landscape of the deforming nucleus. Very asymmetric fusion-fission reactions at energy close to the Coulomb barrier, produce well-defined conditions of the compound nucleus formation, where processes such as quasi-fission, pre-equilibrium emission and incomplete fusion are negligible. In the same time, the excitation energy is sufficient to reduce significantly structural effects, and mostly the macroscopic part of the potential is responsible for the formation of the fission fragments. We use inverse kinematics combined with spectrometers to select and identify the fission fragments produced in $^{238}$U+$^{12}$C at a bombarding energy close to and well-above the Coulomb barrier. For the first time, the isotopic yields are measured over the complete atomic-number distribution, between Z=30 and Z=63. The experimental set-up also allows to identify transfer-induced reactions, which lead to low-energy fission where the nuclear shell structure shows a strong influence on the fission-fragment distributions. The resulting set of data gives the possibility to observe the fission fragment properties over a wide range of excitation energy, and they reveal the vanishing of the shell effects in the potential energy of the fissioning nucleus, as well as the influence of fission dynamics., Comment: Invited Plenary Talk given at the 11th International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio, Texas, USA, May 27-June 1, 2012. To appear in the NN2012 Proceedings in Journal of Physics: Conference Series (JPCS)

Expérience GANIL/VAMOS-LISE; International audience; Two fission experiments have been performed at GANIL using 238U beams at different energies and light targets. Different fissioning systems were produced with excitation energies from 10 to 230 MeV and their decay by fission was investigated with GANIL spectrometers. Preliminary fission-fragment isotopic distributions have been obtained. The evolution with impinging energy of their properties, the neutron excess and the width of the neutron-number distributions, gives important insights into the dynamics of fusion-fission mechanism.

Based on the systematics for hard photon production a scheme is suggested which relates the hard-photon multiplicity observed in intermediate energy heavy ion reactions to the impact parameter. The method is applied to data obtained in an exclusive experiment of the reaction $^{40}\mathrm{Ar}$${+}^{158}$Gd at 44 MeV/nucleon, demonstrating the usefulness of this new approach.

In a calorimeter with silicon readout, operated at the CERN-Proton Synchrotron, the use of a combination of low-Z (Fe) and high-Z (Pb) materials as absorbers allows the transformation of the electron energy distribution of the incident showers in two media with different critical energies via the filtering effect. As a result, a ratio varying from e/π>1 to e/π

A measurement of the single-spin asymmetry A(N) in P up + P --> pi-0 + X at 200 GeV with x(F) = O shows a transition in the production process from a "low-x(T)" regime with A(N) = 0, through an intermediate region of negative asymmetry, to a "high-x(T)" regime with A(N) > 0.3. This transition occurs at x(T) almost-equal-to 0.4 and is consistent with x(T)-scaling of A(N) in pion production using polarized beams or targets from square-root -s = 5.2 to 19.4 GeV. Results for A(N) in eta-production by polarized protons and in pi-0 production by polarized antiprotons are also presented.

We investigated di-nuclear system formation with successive nucleon transfer at beam energies at and below the barrier in the superheavy systems 64 28 Ni + 207 82 Pb ( Z p r o j . + Z t a r g e t = 110 ) and 238 92 U + 238 92 U ( Z p r o j . + Z t a r g e t = 184 ). In both collision systems we observed a massive transfer of nucleons correlated with the dissipation of the entire kinetic energy. The results are in accordance with the two-center shell model which assumes the formation of a di-nuclear system as first step to fusion. The experiments have been performed at the velocity filter SHIP (GSI) and at the VAMOS spectrometer (GANIL).

International audience; Based on a multibeam high intensity driver (5mA of deuterons, 1mA of heavy ions) a detailed project study for Spiral2 was started in November 2002 in a large collaboration. Fission rates of up to 1013/s will be possible with standard density UC (2.3g/$cm^3$), and up to 1014/s with high density (11g/$cm^3$) UC. Fission may be induced either by neutrons from a converter, or with direct beams. The multibeam driver will allow other high intensity beams, with energies up to 14MeV/nucleon for A/Q = 3. The radioactive ions will be accelerated by the existing CIME cyclotron, with energies of 1.7-25MeV/nucleon.

The analyzing power in inclusive charged pion production has been measured using the 200 GeV Fermilab polarized proton beam. A striking dependence in x(F) is observed in which A(N) increases from 0 to 0.42 with increasing x(F) for the pi+ data and decreases from 0 to -0.38 with increasing x(F) for pi- data. The kinematic range covered is 0.2 less-than-or-equal-to x(F) less-than-or-equal-to 0.9 and 0.2 less-than-or-equal-to p(T) 2.0 GeV/c. In a simple model our data indicate that at large x(F) the transverse spin of the proton is correlated with that of its quark constituents.

The single-spin asymmetry A{sub N}(anti pp) for inclusive {pi}{sup 0} production at 0.5 < p{sub t} < 2GeV/c by 200 GeV transversely-polarized antiprotons on protons has been measured at Fermilab over a wide range of x{sub F}. We observe that A{sub N}(anti pp) has the same sign, a similar x{sub F} dependence, and about half the magnitude as A{sub N}(pp) for {pi}{sup 0} production by protons. We also present the ratio of the spin-averaged sections for {pi}{sup 0} production by antiproton and by protons. (orig.).

In an Si/U hadron calorimeter, using a combination of low-Z and high-Z materials for the absorber allows the reduction of the calorimeter response to the electromagnetic component of the incoming hadronic showers (the local hardening effect). As a result, a ratio varying from e/ pi >1 to e/ pi >

The possibility of observing neutrinoless double {beta} decay offers the opportunity of determining the effective neutrino mass if the nuclear matrix element were known. Theoretical calculations are uncertain, and measurements of the occupations of valence orbits by nucleons active in the decay can be important. The occupation of valence neutron orbits in the ground states of {sup 76}Ge (a candidate for such decay) and {sup 76}Se (the daughter nucleus) were determined by precisely measuring cross sections for both neutron-adding and removing transfer reactions. Our results indicate that the Fermi surface is much more diffuse than in theoretical calculations. We find that the populations of at least three orbits change significantly between these two ground states while in the calculations, the changes are confined primarily to one orbit.

International audience; In the framework of the production of radioactive ion beams by the isotope separator online method, a new system has been developed at GANIL/SPIRAL I to produce multicharged alkali ions. The principle, referred to as the “direct 1+/N+ method,” consists of a surface ionization source associated with a multicharged electron-cyclotron-resonance ion source without an intermediate mass separator. This new system has been tested online using a 48Ca primary beam at 60.3 A MeV. The experimental evidence of the direct 1+/N+ process has been obtained for a potential difference between the two sources of 11 V and with a 1+/N+ charge breeding efficiency of 0.04% for 47K5+. This value is significantly lower than the value of 6% obtained for stable K ions with the standard 1+/N+ method. A possible explanation is given in the text.

International audience; Production of Rb, Cs and Fr isotopes from uranium carbide targets of a high density has been investigated. The UC target material with a density of 12 g/cm3 was prepared in a form of pellets of 2 mm thickness, 11 mm in diameter and grain dimensions of about 20 microns. Two targets were tested on-line at the same temperature conditions: a) a reference small target with a thickness of 4.5 g/cm2; b) a big massive target with a thickness of 91 g/cm2. The yields and release efficiencies of the nuclides with the half-lives from some minutes to some milliseconds produced from the investigated targets have been presented. A preliminary analysis of the obtained results has shown an increase of the produced nuclide yields proportionally to the target thickness even for very short-lived isotopes 214Fr (T1/2=5 ms) and 219Fr (T1/2=20 ms). One month off-line heating test of a big target at a temperature of 2000 °C has been conducted. The yields and release of Rb, Cs and Fr measured on-line before and after the heating test coincided in the limits of measurement errors that demonstrated the conservation of the developed target unit parameters. The construction of a big target with the mass about 0.7 kg prepared presently at IRIS has been discussed.

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.

The production of neutron-rich Ag, In and Sn isotopes from a uranium carbide target of a high density has been investigated at the IRIS facility in the PLOG (PNPI-Legnaro-GANIL-Orsay) collaboration. The UC target material with a density of 12 g/cm3 was prepared by the method of powder metallurgy in a form of pellets of 2 mm thickness, 11 mm in diameter and grain dimensions of about 20 μm. The uranium target mass of 31 g was exposed at a 1 GeV proton beam of intensity 0.05–0.07 μA. For the ionization of the produced species the electron beam–plasma ionization inside the target container (ionizing target) has been used. It was the first experiment when the new high density UC target material was exploited with the electron–plasma ionization. Yields of Sn isotopes have been measured in the target temperature range of (1900–2100) °C. The yields of some Pd, In and Cd isotopes were measured as well to compare to previously measured ones from a high density uranium carbide target having a ceramic-like structure. For the first time a nickel isotope was obtained from a high density UC target.

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.

International audience; Production of on-line mass separated neutron-rich isotopes using fission induced by 1 GeV protons on high-density uranium targets (typically 11 g/cm3) has been investigated for several years at the IRIS facility. Here we review some of the achievements during the years up to 2006 and the perspectives. In particular, we present a comparison of yields in p and n-induced fission, enhancements by secondary neutrons, a comparison with lower-density targets used at PARRNe and ISOLDE for Rb and Cs isotopes and preliminary results obtained with a new UC target material.