7Li quasi-free scattering off the alpha-cluster in 9Be nucleus

Spectra of coincident charged particles from the reactions induced by a 52 MeV 7Li beam incident on a beryllium target were measured. Strong contributions of the 7Li quasi-free scattering off the alpha-cluster in 9Be nucleus were observed. This observation supports the conclusions from the study of complete fusion of weakly bound light nuclei at low energies that the "fragility" of the nuclei makes their fusion less probable.Comment: Short Note, 3 pages, 3 Postscript figures, latex with The European Physical Journal style, to be published in The European Physical Journal

Indirect measurements of lithium isotopes destruction cross section in astrophysical environment

Obtaining information on low-energy cross sections is essential for understanding the Universe. Due to the presence of Coulomb barrier and the electron clouds this is usually done by means of theoretical extrapolations. Several indirect methods have been suggested to overcome these difficulties and among them the Trojan Horse Method has already been successful in several cases, which are briefly reviewed in this paper. Some astrophysical implications are also discussed

Improved cross section measurement for the 7Li(p,alpha)4He reaction and its importance for primordial nucleosynthesis and the lithium problem

The 7Li(p,alpha)4He bare nucleus reaction rate plays a crucial role in primordial nucleosynthesis and lithium depletion. But the measurement of the bare nucleus cross section is usually very difficult because of the presence of the Coulomb barrier and the electron screening effect. The Trojan Horse Method (THM) can be applied to extract the energy dependence of Sb(E) at very low energies without any extrapolation, by measuring the cross section of a proper three body process and has been applied to the 7Li(p,alpha )4He reaction. The value deduced from this experiment is Sb(0)=55 +/- 3 keV*b. From the obtained Sb(E) values it is also possible to measure U_e=330+/-40 eV. The astrophysical implications of these measurements are discussed in the case of solar lithium problem and primordial nucleosynthesis

The alpha-C-12 scattering studied via the Trojan-Horse method

The Trojan-horse method has been suggested as a means to study a two-body reaction at astrophysical energies via a three-body breakup reaction. In order to test this method the Li-6(C-12,alpha(12)C)H-2 reaction was studied in a kinematically complete experiment at an incident energy of 18 MeV. Coincidence spectra show the presence of the quasi-free alpha-C-12 scattering process. The excitation function of the three-body reaction is calculated in the plane wave impulse approximation assuming quasi-free scattering and is compared with the experimental data. Also, the excitation function of the virtual a-12C elastic scattering is extracted from the three-body reaction cross section at low deuteron momenta and compared with the behaviour of the free scattering cross section