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Due to their high selectivity, transfer and sequential decay reactions are powerful tools for studies of both single particle (nucleon) and cluster states in light nuclei. Their use is particularly simple for investigations of α-particle clustering (because a-particle has Jπ=0+, which simplifies spin and parity assignments to observed cluster states), but they are also easily applicable to other types of clustering. Recent results on clustering in neutron-rich isotopes of beryllium, boron and carbon obtained measuring the 10B+10B reactions (at 50 and 72 MeV) are presented. The highly efficient and segmented detector systems used, built from 4 Double Sided Silicon Strip Detectors (DSSSD) allowed detection of double and multiple coincidences and, in that way, studies of states populated in transfer reactions, as well as their sequential decay. [ABSTRACT FROM AUTHOR]

The experimental elastic scattering angular distributions of the collisions involving the weakly bound nuclei 6,7Li and the halo nucleus 6He on the same 64Zn target at several energies around the Coulomb barrier were measured at the Laboratori Nazionali del Sud (LNS, Italy), and the Cyclotron Research Center, Louvain La Neuve (Belgium), respectively. The experimental elastic scattering angular distributions of the 6,7Li + 64Zn systems have been analyzed within the continuum-discretized coupled-channels method, while the 6He + 64Zn data have been compared with both continuum-discretized coupled-channels and coupled-reaction-channels calculations. [ABSTRACT FROM AUTHOR]

The experimental elastic scattering angular distributions for the weakly bound nuclei 6,7Li and for the halo nucleus 6He on the same 64Zn target at several energies around the Coulomb barrier were measured at the Laboratori Nazionali del Sud (LNS, Italy) and at the Cyclotron Research Center, Louvain La Neuve (Belgium), respectively. The measured elastic scattering angular distributions of these three systems at the same center of mass energy have been compared. The experimental data of the 6,7Li+ 64Zn systems have been analyzed within the CDCC method, while the 6He+64Zn data have been compared with both both CDCC and CRC calculations. [ABSTRACT FROM AUTHOR]

The results concerning the study of 6Li+120Sn and 7Li+119Sn systems are presented. These two sistems are characterised by very similar structures of the interacting nuclei and by different Q-value for oneand two- neutron transfer. Our aim is to disentangle the possible effects due to the different n-transfer Q-values, at sub-barriers energies, by comparing the two fusion excitation function. In these experiments the fusion cross section has been measured by using a stack activation technique. No particular differences in the two fusion excitation functions have been observed. [ABSTRACT FROM AUTHOR]

In March 2013, the Nemo Phase-2 tower has been successfully installed at 100 km off-shore Capo Passero (Italy) and 3500 m depth. This 8-floor tower hosts 32 10-inch PMT's. Results from optical background measurements are presented. In particular, the analyzed rates show stable and low baseline values, compatible with the contribution of 40K light emission, with a small percentage of light bursts due to bioluminescence. All these features are a confirmation of the stability and good optical nature of the site. [ABSTRACT FROM AUTHOR]

Elastic scattering angular distributions and heavy residue production cross sections have been measured at different energies around the Coulomb barrier for the systems 6,7Li+64Zn. Optical model fits of the elastic angular distributions were performed using a renormalized double folding potential and absence of usual threshold anomaly in the optical potential was found. Excitation functions for heavy residue production have been measured using an activation technique. Comparison of the data with the results of different calculations show that complete fusion is the dominant reaction mechanism above the barrier, whereas the heavy residue yield below the barrier is mainly due to incomplete fusion and transfer. [ABSTRACT FROM AUTHOR]

In this work is reported a study on the efficiency for full energy reconstruction of double sided silicon strip detectors. In order to investigate the effect of the electrode segmentation on the detector response signals, of both polarities for each side of the detectors was acquired at the same time. The efficiency for full energy reconstruction was studied as a function of the detector bias and the incident particle energy. [ABSTRACT FROM AUTHOR]

In this contribution, results of experiments performed with the three Beryllium isotopes 9,10,11Be on a medium mass 64Zn target, at a center of mass energy of ≈1.4 the Coulomb barrier, will be discussed. Elastic scattering angular distributions have been measured for the 9,10Be reactions. In the 11Be case the quasielastic scattering angular distribution was obtained. In the halo nucleus case, the angular distribution exhibit a non-Fresnel-type pattern with a strong damping of the Coulomb-nuclear interference peak. Moreover, it is found that the total reaction cross-section for the halo nucleus induced collision is more than double the ones extracted in the collisions induced by the non-halo Beryllium isotopes. A large contribution to the total-reaction cross-section in the 11Be case could be attributed to transfer and/or break-up events. [ABSTRACT FROM AUTHOR]

The 12C(α,γ)16O reaction plays an important role in helium burning in massive stars and their evolution. However, despite many experimental studies, the low-energy cross section of 12C(α,γ)16O still highly uncertain. The extrapolation of the measured cross sections to stellar energies (E∼300 keV) is made difficult by the presence of the two sub-threshold states at 6.92 and 7.12 MeV of 16O. In order to further investigate the contribution of these two-subthreshold resonances to the 12C(α,γ)16O cross section, we performed a new determination of the α -reduced widths via a measurement of the transfer reaction 12C(7Li,t)16O at two incident energies, 34 and 28 MeV. The measured and calculated differential cross sections will be presented as well as the obtained spectroscopic factors and the α -reduced widths. [ABSTRACT FROM AUTHOR]

The reaction 13C(α,n)16O is considered as the main neutron source for s-process in low-mass asymptotic giant branch stars. At low energies of astrophysical interest, the contribution of the subthreshold state 6.356 MeV of 17O to the 13C(α,n)16O cross section should be taken into account. However, the results of previous studies of this contribution lead to different conclusions. Hence, we investigated the effect of this resonance on the astrophysical S-factor through a new precise measurement of the alpha spectroscopic factor, Sα, of the 6.356 MeV state using the transfer reaction 13C(7Li,t)17O at two different incident energies. The measured angular distributions and the obtained spectroscopic factors will be presented as well as their impact on C(α,n)16O cross section and reaction rate. [ABSTRACT FROM AUTHOR]

The low-energy levels of 19Na were studied in the center-of-mass energy (ECM) range from 2.6 to 3.4 MeV, by using the elastic and inelastic scattering methods in inverse kinematics. The 18Ne+p scattering reactions, leading to the ground state and the first excited state of 18Ne, were investigated by using a 66 MeV radioactive 18Ne beam and a polyethylene (CH2)n target. The experimental methods and the set-up are described and preliminary results are presented. [ABSTRACT FROM AUTHOR]

The ground state of particle-unbound nuclei is observed as a resonance. According to the Heisenberg's uncertainty principle, the shorter is the lifetime of the state the broader is the resonance. The Breit-Wigner formalism describes perfectly the shape of the resonance when energy-dependent partial-widths are used. In the low energy tail of a ground state resonance near the particle-emission threshold, the partial-width for the emission of a charged particle through the Coulomb barrier is drastically reduced. The fact that the proton decay is strongly hindered seems to be equivalent to the assertion that the decay of the proton is strongly delayed. In this interpretation and as an example, possible consequences are discussed in astrophysical context. Two reactions 15O(p,β+)16O and 15O(p,γ)(β+)16O are proposed as new pathways to bypass the 15O waiting point. Cross-sections were calculated after precise measurements of energies and widths of the proton-unbound 16F low lying states, obtained using the H(15O,p)15O reaction. These measurements were performed at SPIRAL—GANIL facility using an 15O post-accelerated radioactive beam. [ABSTRACT FROM AUTHOR]

Two reactions 15O(p,β+)16O and 15O(p,γ)(β+)16O are proposed as new pathways to bypass the 15O waiting point in astrophysical context. The later reaction is found to have a surprisingly high cross section, approximately 1010 times higher than the first reaction. These cross sections were calculated after precise measurements of energies and widths of the proton-unbound 16F low lying states, obtained using the H(15O,p)15O reaction. The large (p,γ)(β+) cross section can be understood to arise from the more efficient feeding of the low energy wing of the ground state resonance by the gamma decay. The implications of the new reactions are discussed. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

The 6He+6,7Li and 6He+12C scatterings and reactions have been studied using a 18 MeV 6He radioactive beam. A large variety of processes have been observed and analysed: elastic, inelastic and quasi-free scatterings and transfer, sequential decay and compound nucleus reactions. Results supporting the existence of molecule-like structures in 10Be have been obtained. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

The study of reaction mechanisms in collisions induced by halo and/or weakly bound nuclei around the barrier has recently been the subject of many theoretical and experimental papers. Here we discuss our recent results concerning the study of the systems 13N+9Be and 6He+64Zn. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

The cross section of 8Li(α,n)11B is very important for the study of primordial nucleosinthesys models. In this paper we report on the production of a 8Li beam via the 7Li(d,p)8Li reaction at the Laboratori Nazionali del Sud. Also, a novel experimental technique for measuring the reaction 8Li(α,n)11B at energies of astrophysical interest has been implemented and tested. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

Because of the Coulomb barrier, reaction cross sections in astrophysics cannot be accessed directly at the relevant Gamow energies, unless very favourable conditions are met (e.g. LUNA - underground experiments). Theoretical extrapolations of available data are then needed to derive the astrophysical S(0)-factor. Various indirect processes have been used in order to obtain additional information on the parameters entering these extrapolations. The Trojan Horse Method is an indirect method which might help to bypass some of the problems typically encountered in direct measurements, namely the presence of the Coulomb barrier and the effect of the electron screening. However, a comparison with direct data in an appropriate energy region (e.g. around the Coulomb barrier) is crucial before extending the method to the relevant Gamow energy. Additionally, experimental and theoretical tests are needed to validate the assumptions underlying the method. The application of the Trojan Horse Method to some cases of interest is discussed. [ABSTRACT FROM AUTHOR]

The Trojan-Horse method has been applied to the [sup 6]Li([sup 12]C,α[sup 12]C)[sup 2]H reaction at 18 MeV in order to study the two-body α-[sup 12]C interaction around the Coulomb barrier. Coincidence spectra show clear evidence of the quasi-free α-[sup 12]C scattering, in good agreement with calculations performed in the framework of the Plane Wave Born Approximation. The virtual excitation function of the α-[sup 12]C elastic scattering has been extracted and compared with the behavior of the free scattering cross section. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The Trojan Horse Method has been applied to obtain information about [sup 7]Li(p,α)[sup 4]He reaction at astrophysical energies. The [sup 7]Li(d,α n)[sup 4]He reaction has been used and the two body reaction cross section for the [sup 7]Li(p,α)[sup 4]He has been extracted together with its astrophysical factor S(E). © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The [sup 6]Li(d,α)[sup 4]He reaction, whose astrophysical importance is connected to the primordial nucleosynthesis in the framework of the Inhomogeneous Big Bang, has been studied by using the Trojan Horse Method (THM). We derive and discuss the cross section and the astrophysical S(E)-factor for E[sub cm]=0.025-0.7 MeV. Results are compared with data from a direct measurement. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

New fusion data for the 4He+64Zn system at sub-barrier energies are measured to cover the same energy region of previous measurements for 6He+64Zn. Aim of the experiment was to compare the fusion excitation functions for the two system to investigate on the effects of the 6He neutron-halo structure on the fusion reaction mechanism at energies around the Coulomb barrier. The fusion cross section was measured by using an activation technique. Comparing the two systems, we observe an enhancement of the fusion cross section in the reaction induced by 6He, at and below the Coulomb barrier. [ABSTRACT FROM AUTHOR]

Elastic-scattering angular distributions for the 6Li+64Zn system were measured at energies from below to above the Coulomb barrier. The experimental data were analyzed within the optical model to study the energy dependence of the interaction potential. The results suggest the presence of the breakup threshold anomaly. Preliminary results on the fusion cross-sections for the same system are also reported. [ABSTRACT FROM AUTHOR]

The inverse kinematics thick target scattering method (TTIK) has been used to study the 8Li elastic scattering on 4He in order to investigate 8Li-α cluster configurations in excited states of 12B. A 8Li beam, provided by the radioactive beam facility EXCYT, at Ebeam = 30.6 MeV, passing through helium thick target, continuosly decreases its energy inducing elastic scattering starting from the initial energy down to zero. Four ΔE-E double stage silicon detector telescopes were used to detect the recoil α-particles coming from the scattering. Event by event time measurement between beam particles passing through a MCP detector and α-particles impinging on ΔE stage allows elastic from inelastic events discrimination, thus representing an improvement of the TTIK method. In this paper the used experimental technique and some preliminary results will be briefly described. [ABSTRACT FROM AUTHOR]

Few-body methods provide very useful tools to solve different problems important for nuclear astrophysics. Some of them are discussed below. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Focus of this article is put on a method of compensating for non-uniformity of 50μm thin silicon detectors, rather than measurement results. The same high sensitivity of particle identification on thin-detector thickness enables to accurately model thickness variation using the measurement data, rather than measuring the thickness separately. [ABSTRACT FROM AUTHOR]

Fusion cross sections for the 6Li+120Sn and 7Li+119Sn systems have been measured. We aim to search for possible effects due to the different neutron transfer Q-values, by comparing the fusion cross sections for the two systems below the barrier. This experiment is the first step of a wider systematic aiming to study the above problems in collisions induced by stable and unstable Li isotopes on tin all forming the same compound nucleus. [ABSTRACT FROM AUTHOR]

The reactions 9,10,11Be+64Zn have been studied at energies around the Coulomb barrier in order to better understand the role played by the halo features on the reaction dynamics. Preliminary results on such studies will be reported in this paper. [ABSTRACT FROM AUTHOR]