Nuclear astrophysics using radioactive nuclear beams is one of the major research topics in Louvain-la-Neuve. Recently, experiment aiming at the measurement of (α,γ), and (α,p) reactions have been performed. The 15O(α,γ)19Ne reaction was studied using an indirect method based on the study of the 18Ne(d, p)19Ne*. Preliminary results of a new analysis of this experiment are presented here. The new mass recoil separator ARES, coupled to the new cyclotron CYCLONE-44, is now operational. The ARES project status and results of performance tests are reported here.  2002 Elsevier Science B.V. All rights reserved. * Corresponding author. E-mail address: cherubini@fynu.ucl.ac.be (S. Cherubini). 1 Present address: Università di Catania and INFN-Laboratori Nazionali del Sud, Catania, Italy. 0375-9474/02/$ – see front matter  2002 Elsevier Science B.V. All rights reserved. PII: S0375-9474(01)01657-8 S. Cherubini et al. / Nuclear Physics A 701 (2002) 632c–636c 633c 1. Indirect study of 15O(α,γ)19Ne reaction The CNO cycle takes place in stellar environments where carbon is present and temperatures are of the order of 2 × 107 K or higher. This cycle transforms hydrogen to helium by a sequence of (p,γ), (p,α) reactions and β+ decays. As the temperature increases to 108 K the so called hot-CNO cycles take place. These cycles include p captures by β unstable isotopes. The 13N(p,γ)14O reaction initiates the hot-CNO cycles, while the 15O(α,γ)19Ne(p,γ)20Na reaction chain may lead to an escape from the CNO cycles and to an enhancement of the abundances of the seed isotopes for the subsequent rp-processes, which will synthesize heavier elements. The measurement of the 15O(α,γ)19Ne reaction cross section in the energy region of interest (roughly 500 keV), where some 19Ne levels are present [1], is then very important in order to understand whether this escape from CNO cycles is possible or not. Fig. 1. Reconstructed 19Ne→ 15O+ α decay Q value. The three pictures refer to three different runs performed during the experiment. 634c S. Cherubini et al. / Nuclear Physics A 701 (2002) 632c–636c Unfortunately, in spite of a 15O beam being available at Louvain-la-Neuve, a direct measurement of the cross section of interest—of the order of 100 pb—presents many problems. In order to overcome some of them, it was proposed to use an indirect method: the 19Ne states which lie inside the Gamow window (4.033 MeV and above) can be populated via the 18Ne(d, p)19Ne* process and from their decay into 15O + α one can infer information on the inverse process, namely the direct capture of 15O on α [2,3]. The experiment was performed in three runs and different 18Ne beam energies (from 45 to 54 MeV) were used to bombard CD2 targets. The experimental setup was based on three Louvain–EdinburghDetectors Arrays (LEDA). Each LEDA (fully described in [4]) is a disk shaped multistrip silicon detector with an outer radius of nearly 15 cm and a central hole with of 4 cm, divided into 8 sectors with 16 strips each, for a total of 128 strips. These detector arrays allow for an almost complete covering of the φ azimuth angle while the distances between the three LEDAs (mounted in a coaxial geometry) to the target were such that the θ angular regions roughly from 4 to 27 and from 125 to 155 degrees were covered. Two different data analysis were performed. One of them is presented in another contribution to this conference [5], while the other is still in progress and very preliminary results are reported here. In both of the two analysis, events coming from the 18Ne(d, p)19Ne* (→ 15O + α) process were selected applying proper cuts in phase space. In particular a proton tagging was applied. While events with a backward-going proton are particularly clean, theoretical calculations showed that an advantage in statistics could come from the tagging of forward going proton. Owing to the characteristics of the available detectors, the setup was not fully optimized for this particular channel. Nonetheless, we performed an analysis of part of the data taken in the 54 MeV run using this event selection and it was possible to reconstruct spectra showing peaks due to the presence of the 19Ne states, as shown in Fig. 1. These preliminary results, though partial, showed that this type of analysis can give interesting information and it is presently being extended to the full data set. 2. Astrophysics recoil separator Coupled to the new cyclotron CYCLONE44 [6] the Astrophysics REcoils Separator (ARES) has recently become operational at Louvain-la-Neuve. A schematic view of the apparatus is shown in Fig. 2. ARES is conceived for studying in first instance (p,γ) reactions of astrophysical interest involving radioactive nuclei in inverse kinematics. These reactions lead typically to product nuclei contained in a narrow forward cone (opening ∼ ±1◦) around the beam direction. The spectrometer has to separate the beam from the reaction products within this cone [7]. In the past few month, new equipment for experimental work has been installed and performance tests have been performed. In particular, the new integrated target-scattering chamber and the ion chamber were mounted. The target-scattering chamber comprises a target box, a detector box for monitor counters and/or a LEDA, two collimators at the entrance and at the exit of the target box and two target ladders with integrated Faraday cup. The ion chamber uses an anode– S. Cherubini et al. / Nuclear Physics A 701 (2002) 632c–636c 635c Fig. 2. CYCLONE44—ARES setup. grid–cathode assembly for dE/dx energy loss and a 100 mm2 Si detector for E energy measurement. Tests using a three line α source (239Pu, 241Am, 244Cm) gave an overall resolution δE < 14 keV at FWHM and δE/E ∼ 0.25%. The new beam line for astrophysical studies at CYCLONE44 has been completed and beams of 14N, 15N and 19F were successfully transported through the optical elements of the separator with 90–100% transmission efficiency. The performances of the beam optics were as expected from beam transport calculations and Monte Carlo simulations. A rejection factor for a 9.1 MeV 14N beams of > 1010 was obtained. The results for suppression with the 19F beams were worse owing to some beam instabilities that have been understood and are presently solved. We could, however, remeasure the resonant scattering to the J = 1+ resonance in 20Ne at Ecm = 635 keV, reproducing the wellknown interference between resonant and Coulomb amplitudes. The ion chamber was tested with 19F beams giving an excellent dE/dx resolution. At E/E of ∼ 20%, the energy loss resolution δ( E)/ E = 5.1% was achieved. In order to suppress the direct beam component—including degraded energy tails— beyond the 10−12 level, as required for nuclear astrophysics measurements, a contribution of three orders of magnitude in the suppression factor has to be obtained from the energyE, energy loss dE/dx and the time-of-flight TOF information. Tests done using a simple TOF information coming from the radio frequency of the cyclotron confirmed that at least one order of magnitude in the suppression factor is achievable from a TOF measurements. A TOF setup based on a microchannel plate and fast electronics will be installed on the ARES setup in the near future.

This paper reports the last developments and the status of the UCL irradiation facilities for radiation hardness assurance. Protons up to 62MeV, heavy ions up to Xenon, neutrons and Co-60 are available.

The in-gas laser ionization and spectroscopy (IGLIS) technique was applied on the Ac212-215 isotopes, produced at the Leuven Isotope Separator On-Line (LISOL) facility by using the in-gas-cell and the in-gas-jet methods. The first application under on-line conditions of the in-gas-jet laser spectroscopy method showed a superior performance in terms of selectivity, spectral resolution, and efficiency in comparison with the in-gas-cell method. Following the analysis of both experiments, the magnetic-dipole moments for the (212-215)Acisotopes, electric-quadrupole moments and nuclear spins for the Ac-214,Ac-215 isotopes are presented and discussed. A good agreement is obtained with large-scale nuclear shell-model calculations by using a Pb-208 core.

Resonant laser ionization and spectroscopy are widely used techniques at radioactive ion beam facilities to produce pure beams of exotic nuclei and measure the shape, size, spin and electromagnetic multipole moments of these nuclei. However, in such measurements it is difficult to combine a high efficiency with a high spectral resolution. Here we demonstrate the on-line application of atomic laser ionization spectroscopy in a supersonic gas jet, a technique suited for high-precision studies of the ground- and isomeric-state properties of nuclei located at the extremes of stability. The technique is characterized in a measurement on actinium isotopes around the N =126 neutron shell closure. A significant improvement in the spectral resolution by more than one order of magnitude is achieved in these experiments without loss in efficiency.

Received 21 June 2016DOI:https://doi.org/10.1103/PhysRevAccelBeams.19.079901This article is available under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.© 2016 American Physical Society

The Cyclotron Resources Center of the Louvain-la-Neuve University is developing a new electron cyclotron resonance ion source to increase the energy of the accelerated beam by injection of higher charge state ions into the cyclotron. The design of the source is based on a 17.3 GHz frequency and classical coils to produce the axial field. The field reaches 2 T at the injection side and 1.2 T at extraction. The total power consumption for the coils is limited to 80 kW. The design features of the source are presented.

"Beta beams" produce collimated pure electron (anti) neutrino beams by accelerating beta active ions to high energies and having them decay in a racetrack shaped storage ring of 7 km circumference, the decay ring. EUROnu beta beams are based on CERN infrastructures and existing machines. Using existing machines may be an advantage for the cost evaluation, but will also constrain the physics performance. The isotope pair of choice for the beta beam is He-6 and Ne-18. However, before the EUROnu studies one of the required isotopes, Ne-18, could not be produced in rates that satisfy the needs for physics of the beta beam. Therefore, studies of alternative beta emitters, Li-8 and B-8, with properties interesting for a beta beam have been proposed and have been studied within EUROnu. These alternative isotopes could be produced by using a small storage ring, in which the beam traverses a target, creating the Li-8 and B-8 isotopes. This production ring, the injection linac and the target system have been evaluated. Measurements of the cross section of the reactions to produce the beta beam isotopes show interesting results. A device to collect the produced isotopes from the target has been developed and tested. However, the yields of Li-8 and B-8, using the production ring for production of Li-8 and B-8, is not yet, according to simulations, giving the rates of isotopes that would be needed. Therefore, a new method of producing the Ne-18 isotope has been developed and tested giving good production rates. A 60 GHz ECRIS prototype, the first in the world, was developed and tested for ion production with contributions from EUROnu. The decay ring lattices for the Li-8 and B-8 have been developed and the lattice for He-6 and Ne-18 has been optimized to ensure the high intensity ion beam stability.

The goal of the European project EUROnu is the study of different ways to produce the future neutrino beams. One of them, proposed by C. Rubbia, is based on the production of Li-8 and B-8 nuclei and their post-acceleration. Within the "beta beams" work package of this project, our task is to study experimentally the production and collection efficiency of these 2 nuclei. Our R&D work is organised in two phases: first - design and construction of a collection device which will be validated with Li-8; second - experimental study of the possible ways to extract B-8 from the collection device.

The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the Fréjus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of μ+ and μ- beams in a storage ring. The far detector in this case is a 100 kt Magnetised Iron Neutrino Detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neutrinos come from the decay of beta emitting isotopes, in particular 6He and 18Ne, also stored in a ring. The far detector is also the MEMPHYS detector in the Fréjus tunnel. EUROnu has undertaken conceptual designs of these facilities and studied the performance of the detectors. Based on this, it has determined the physics reach of each facility, in particular for the measurement of CP violation in the lepton sector, and estimated the cost of construction. These have demonstrated that the best facility to build is the Neutrino Factory. However, if a powerful proton driver is constructed for another purpose or if the MEMPHYS detector is built for astroparticle physics, the Super Beam also becomes very attractive.

The goal of the European project EUROnu is the study of different ways to produce the future neutrino beams. One of them, proposed by C. Rubbia, is based on the production of 8Li and 8B nuclei and their post-acceleration. Within the "beta beams" work package of this project, our task is to study experimentally the production and collection efficiency of these 2 nuclei. Our R&D work is organised in two phases: first – design and construction of a collection device which will be validated with 8Li; second – experimental study of the possible ways to extract 8B from the collection device.

The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the Frejus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of mu(+) and mu(-) beams in a storage ring. The far detector in this case is a 100 kt magnetized iron neutrino detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neutrinos come from the decay of beta emitting isotopes, in particular He-6 and Ne-18, also stored in a ring. The far detector is also the MEMPHYS detector in the Frejus tunnel. EUROnu has undertaken conceptual designs of these facilities and studied the performance of the detectors. Based on this, it has determined the physics reach of each facility, in particular for the measurement of CP violation in the lepton sector, and estimated the cost of construction. These have demonstrated that the best facility to build is the Neutrino Factory. However, if a powerful proton driver is constructed for another purpose or if the MEMPHYS detector is built for astroparticle physics, the Super Beam also becomes very attractive. DOI: 10.1103/PhysRevSTAB.16.021002

Neutrino oscillations have implications for the Standard Model of particle physics. The CERN Beam has outstanding capabilities to contribute to precision measurements of the parameters governing neutrino oscillations. The FP7 collaboration EUROnu (2008-2012) is a design study that will review three facilities (Super-Beams, and Neutrino Factories) and perform a cost assessment that, coupled with the physics performance, will give means to the European research authorities to make decisions on future European neutrino oscillation facilities. Beta Beams produce collimated pure electron (anti)neutrinos by accelerating beta active ions to high energies and having them decay in a storage ring. Using existing machines and infrastructure is an advantage for the cost evaluation; however, this choice is also constraining the Beams. Recent work to make the Beam facility a solid option will be described: production of Beam isotopes, the 60 GHz pulsed ECR source development, integration into the LHC-upgrades, insure the high intensity ion beam stability, and optimizations to get high neutrino fluxes. The costing approach will also be described.

The Beta-Beam is a concept of large-scale facility that aims at providing pure electronic neutrino and antineutrino beams for the measurement of \( \nu_{e}^{}\) \( \rightarrow\) \( \nu_{\mu}^{}\) oscillations. Beta-decaying nuclides are produced in large amounts in a facility of the scale of EURISOL, and are then post-accelerated and stored at large \( \gamma\) in a racetrack decay ring. We present here a conceptual design of the accelerator chain of a Beta-Beam based at CERN.

We present new data for the reaction Be-7+Be-9 measured at E-lab =23.7 MeV. The elastic scattering angular distribution has been analyzed using the phenomenological optical model and the coupled-channels method. In the latter approach, we assumed a two-cluster model of the Be-7 nucleus, and we included explicitly the ground state and first excited state of this nucleus. The contribution of the inelastic excitation of the Be-7 nucleus to the quasielastic cross sections has been investigated.

The early E⩽511keV gamma-ray emission from novae depends critically on the F18(p,α)O15 reaction. Unfortunately the reaction rate of the F18(p,α)O15 reaction is still largely uncertain due to the unknown strengths of low-lying proton resonances near the F18+p threshold which play an important role in the nova temperature regime. We report here our last results concerning the study of the d(F18,p)F19(α)N15 transfer reaction. We show in particular that these two low-lying resonances cannot be neglected. These results are then used to perform a careful study of the remaining uncertainties associated to the F18(p,α)O15 and F18(p,γ)Ne19 reaction rates.

The 15O(α,α)15O elastic scattering is investigated using a 15O radioactive beam and a He gas cell limited by Mylar windows. The width of a 19Ne state at an excitation energy of 5.35MeV is measured as Γα = 3.2±1.6keV, in agreement with charge symmetry estimate.

We have investigated the low-energy states of N-11 by the elastic scattering method in inverse kinematics using a C-10 beam and a (CD2)(n) target. Recoil protons were detected at 16 laboratory angles theta(lab) - 4.6 degrees - 18.9 degrees in a Delta E - E detector system. Using the R-matrix method to analyse the C-10 + p elastic cross sections, we found N-11 to be unbound with respect to proton emission by 1.54 +/- 0.02 MeV with a decay width of 0.83 +/- 0.03. These results are used to calculate the two-proton decay width of the O-12 ground state.

We have investigated the low-energy states of N-11 by the resonant elastic-scattering method in inverse kinematics using a C-10 beam and a (CH2)(n) target at the CYCLONE facility at Louvain-la-Neuve. Recoil protons were detected at laboratory angles theta(lab)=5.2 degrees-18.3 degrees in a Delta E-E detector system. The absolute C-10+p elastic cross-section data were analyzed in the R-matrix framework. We found N-11 to be unbound with respect to proton emission by 1.54 +/- 0.02 MeV, with a decay width of 0.83 +/- 0.03 MeV. These results are used to calculate the two-proton decay width of the O-12 ground state.