Search

The neutron-rich carbon isotope 15C was postulated to be a halo nucleus (Sn = 1215 keV, S2n = 9395 keV) according to different high-energy experiments. If so, it would be the only halo nucleus exhibiting a “pure” s-wave structure of the ground state. At low collision energies, the effect of this halo structure should manifest as a strong absorption pattern in the angular distribution of the elastic cross section, with a total suppression of the nuclear rainbow due to the large neutron transfer and breakup probabilities, enhanced by the halo configuration. The IS619 experiment, carried out at the HIE-ISOLDE facility at CERN (Switzerland), is the first dynamical study of this nucleus at energies around the Coulomb barrier. It aims to probe the halo structure via the measurement of the elastic cross section on a high-Z 208Pb target. Preliminary results of the elastic cross section are discussed and compared to Optical Model calculations. [ABSTRACT FROM AUTHOR]

A complete study of the 6,7Li + p reactions was performed by measuring the complete net of reaction channels at the energy range of ~ 2 to 5 MeV/nucleon. The experiments were performed at the MAGNEX facility of the Istituto Nazionale di Fisica Nucleare-Laboratori Nazionali del Sud (INFN-LNS) in Catania. The breakup channel was identified by means of a new algorithm, MULTIP, which gives the possibility of following up the decay of the nucleus into two or more constituent particles from the rest frame of the nucleus itself to the laboratory frame. Angular distributions were obtained for all reaction products and were considered within the Continuum Discretized Coupled Channels (CDCC) framework. The results of the CDCC calculations were found in a very good agreement with the experimental data presenting a strong evidence for the important influence of coupling to breakup on the elastic channel. [ABSTRACT FROM AUTHOR]

Elastic scattering data for p+9Be, recently obtained in inverse kinematics, together with data from the literature measured in direct kinematics, were previously considered and evaluated via a Coupled Reaction Channels approach (CRC). This set of data for energies between 1.7 and 15 MeV/nucleon, free from normalization inconsistencies, is analyzed in this work using the microscopic approach of the Jeukenne, Lejeune and Mahaux interaction (JLM). The results show that even at these low energies the data can be well-described within this framework. [ABSTRACT FROM AUTHOR]

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 superconducting linac. [ABSTRACT FROM AUTHOR]

The structure and dynamics of 8He have been studied through the collision process with a 208Pb target at energies of 22 and 16 MeV, above and below the Coulomb barrier, respectively. The energy and angular distributions of the elastically scattered 8He and the 6,4He fragments were measured. In this paper, we discuss the method used to determine the effective position of the beam spot on the reaction target and the scattering and solid angles of each pixel of the detector array. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The interaction of the Radioactive Ion 7Beam Be with the closed proton shell target 58Ni was investigated at two energies around the Coulomb barrier. 7Be scattered ions as well as 3,4He reaction products were measured in a rather wide angular range. The elastic scattering angular distributions were analyzed within the framework of the optical model to extract the total reaction cross section. Extensive theoretical and kinematical calculations were performed to disentangle the origin of 3,4He ions between direct and compound nucleus reactions. [ABSTRACT FROM AUTHOR]

The quasi-elastic scattering angular distribution of the collision 11Be + 64Zn was measured and compared with the elastic scattering angular distribution for its core, the 10Be nucleus on the same target. Optical model and continuum-discretized coupled-channel calculations of the 11Be+64Zn reaction were performed in order to interpret the effect of coupling with the break-up channels on the measured cross-sections. [ABSTRACT FROM AUTHOR]

The dynamics of 8He around the Coulomb barrier is investigated by measuring the energy and angular distribution of the elastic 8He and the 6He and 4He fragment yields in the collision process with a 208Pb target. The experiment was carried out at SPIRAL/GANIL in October 2010. The experimental results will provide information about the relevant reaction mechanisms and the validity of the optical model (OM) when applied to exotic nuclei. In this paper, details of the experimental setup and preliminary results on the elastic scattering for the collision at 22 MeV are presented. [ABSTRACT FROM AUTHOR]

Recent results on the reaction dynamics induced by light radioactive ion beams at Coulomb barrier energies are reviewed. As a general feature, the exotic structure and the weak binding energy of most of these projectiles enhance the reaction probability rather than the fusion cross section, as originally expected. The quest has now moved toward understanding which direct reaction mechanism originates the enhancement. Experimental data showed that n-halo and p-halo nuclei are characterized by a different behavior. Transfer processes enhance the reaction probability for n-halo nuclei, such as 6;8He, while for p-halo nuclei, such as 8B, the breakup channel seems to be mainly responsible for the enhancement. [ABSTRACT FROM AUTHOR]

Experimental data sets of 11Be + 120Sn (Elab = 32MeV) quasielastic scattering and 10Be yield coming from the breakup of the projectile were analyzed by means of the continuum-discretized coupled-channel method. Comparison of the calculations and the experimental data suggests that the root-mean-square radius of the neutron wave function of the 11Be ground state is larger than that deduced previously from a high energy scattering experiment. The largest contribution to the breakup cross-section was found to come form Coulomb breakup, in good agreement with the observed post-acceleration of the detected 10Be. Large Coulomb-nuclear interference effects are found. [ABSTRACT FROM AUTHOR]

We have measured the angular distributions of elastic scattering and6,4He fragments produced in the collisions of an exotic beam of 8He on a 208Pb target at laboratory energies of 18 and 22 MeV, just around the Coulomb barrier (19 MeV). The measurements were performed at the SPIRAL/GANIL facility in Caen, France. In this paper, we present preliminary data on elastic cross sections and discuss the results using optical model and coupled reaction channel calculations. [ABSTRACT FROM AUTHOR]

Dipole polarizability, one of the fundamental properties of a nucleus, studied in elastic scattering experiments has been reviewed here. For strongly bound nuclei the effect of dipole polarizability is usually negligible. However, for weakly bound nuclei, where the dipole strength extends to low excitation energies, it does play a major role. This effect has already been examined in the scattering of the lightest weakly-bound stable nuclei, viz., d, ³He, and 7Li. In the present work we have studied it for the weakly bound unstable borromean nucleus, 6He, using the elastic scattering data available at energies around the Coulomb barrier with a 208Pb target. [ABSTRACT FROM AUTHOR]

Results of irradiation of thin Chemical Vapor Deposition (CVD) diamond detectors with low energy: p, α and 7Li beams are presented. Energy resolution: ΔE/E < 1% of a single crystal detector was achieved. A coincident measurement with two diamond detectors showed time resolution of 100 ps and efficiency above 70%. Despite a high beam flux reaching 109 particles/s cm² the tested detectors showed low dead-time and satisfactory radiation hardness. Perspectives of applying thin CVD diamond detectors in monitoring of a slowed down radioactive beam (RIB) are discussed. [ABSTRACT FROM AUTHOR]