A hitchhiker's guide to the Trojan Horse Method

Owing the presence of the Coulomb barrier at astrophysically relevant kinetic energies, it is very difficult, or sometimes impossible to measure astrophysical reaction rates in laboratory. This is why different indirect techniques are being used along with direct measurements. The THM is unique indirect technique allowing one measure astrophysical rearrangement reactions down to astrophysical relevant energies. The basic principle and a review of the main application of the Trojan Horse Method are presented. A step-by-step approach will be adopted in order to describe the features usually unknown to non-experts

Commissioning of the BRIKEN beta-delayed neutron detector for the study of exotic neutron-rich nuclei

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Trojan Horse estimate of bare nucleus astrophysical S(E)-factor for the (6)Li(p,alpha) (3)He reaction and its astrophysical implications

The (6)Li(p, alpha)(3)He bare nucleus cross-section at astrophysical energies has been indirectly measured in the framework of the Trojan-Horse Method, finding an agreement within the experimental errors with the results of data extrapolations from direct methods. This result is thus an independent check of the extrapolation method used until now. The method of measure is recalled and the results are shown with particular attention to the bare cross section value at the Gamow energy. The quoted agreement between direct and indirect methods is discussed in the context of the surface lithium abundances in stars. It is shown that the problem of stellar lithium abundances is not at the nuclear physics level but it is an astrophysics problem that requires improvements in our knowledge of the mixing mechanisms, the reduction of the uncertainties on the other (non-nuclear) physical inputs, and more precise observational data

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

Experimental determination of the Be-7+p scattering lengths

The Be-7 + p elastic cross section has been measured at the Centre de Recherches du Cyclotron RIB facility at Louvain-la-Neuve in the c.m. energy region from 0.3 to 0.75 MeV by bombarding a proton-rich target with a radioactive 7Be beam. The recoil protons have been detected in the angular range theta(c.m.) = 120.2degrees-131.1degrees and theta(c.m.) = 156.6degrees-170.2degrees using the LEDA system. From a R-matrix analysis of the cross section data. we obtain the energy and the width of the I resonance (E-X = 0.77 MeV). The iota = 0 scattering lengths a(01) = 25 +/- 9 fm (channel spin I = 1) and a(02) = -7 +/- 3 fm (channel spin I = 2) have been deduced. They are compared to values expected from charge-symmetry properties. Implications on the low energy S-factor of the Be-7(p,gamma)B-8 reaction are discussed. (C) 2003 Elsevier Science B.V. All rights reserved