Coulomb Dissociation Method Research Articles

The Coulomb dissociation of 8B and the 8B solar neutrino flux

The rate of the 7Be(p, γ) 8B reaction, directly related to the production of 8B in the sun, is most uncertain and yields one of the largest uncertainty in the standard solar model (SSM) estimate of the 8B solar neutrino flux. We discuss a first attempt to measure this reaction rate via the Coulomb dissociation method. The experiment utilized 46.5 MeV/u 8B radioactive beams, from the RIKEN-RIPS facility and our initial results are consistent with the lower value of the cross section, as measured by Filippone et al., as well as allow for an estimate of the p-wave contribution to the 7Be(p, γ) 8B reaction that needs to be corrected for in the extrapolation to solar energies. Our preliminary result suggests a 8B solar neutrino flux which is 25–30% smaller than predicted by the various SSMs of Bahcall et al.

The coulomb dissociation of 8B and the 8B solar neutrino flux

The rate of the 7 Be ( p, γ ) 8 B nuclear reaction, directly related to the production of 8 B in the sun, is most uncertain and yield one of the largest uncertainty in the standard solar model estimate of the 8 B solar neutrino flux. We discuss a first attempt to measure this reaction rate via the Coulomb dissociation method. Our initial results are consistent with the lower value of the cross section, as measured by Filippone et al., as well as allow for an estimate of the p-wave contribution that needs to be corrected for. Our preliminary result suggest a 8 B solar neutrino flux which is 25–30% smaller than predicted by the various standard solar model of Bahcall et al.

The astrophysical reactions 12C( alpha, gamma )16O and 7Be(p, gamma )8B and Coulomb dissociation experiments.

The use of the Coulomb dissociation method to obtain the cross sections for the radiative capture reactions $^{3}\mathrm{C}$(\ensuremath{\alpha},\ensuremath{\gamma}) $^{16}\mathrm{O}$ and $^{7}\mathrm{Be}$(p,\ensuremath{\gamma}) $^{8}\mathrm{B}$ is investigated. The contribution of the nuclear interaction to the breakup is included. Due to the low binding of the proton in $^{8}\mathrm{B}$ the second reaction is dominated by Coulomb breakup. The effects of Coulomb reacceleration of the fragments and of the excitation of states in the fragments are also studied. Ideal kinematical conditions for the experiments are investigated.

Determination of the astrophysical 13N (p, γ) 14O cross section through the Coulomb dissociation method

The Coulomb dissociation reaction 208Pb( 14O, 13N p) 208Pb was measured at E in = 87.5 MeV/u to determine the radiative width Γ γ of the 1 − state in 14O at E ex = 5.17 MeV. This state dominates the radiative capture process 13N(p, γ) 14O, a key reaction in the hot CNO cycle of hydrogen burning in stars. We have deduced Γ γ = 3.1 ± 0.6 eV with the help of a coupled channel calculation. The validity of the technique was confirmed in the case of the 208Pb( 13N, 12C p) 208Pb reaction exciting the 1 2 + state in 13N whose width is known.

The angular correlation in the coulomb dissociation method for radiative capture processes of astrophysical interest

The angular correlation of fragments emitted after Coulomb excitation into the continuum is studied in view of possible applications to radiative capture processes of astrophysical interest. Applications are given to recently performed 7Li and 6Li breakup experiments, and other possible applications of the method, like 16O → 12C + α and 14O → 13N + p Coulomb dissociation, are discussed. A preliminary analysis is presented of the breakup of 156 MeV 6Li projectiles colliding with 208Pb at some 100 keV relative energy of the fragments α and d. It yields an S-factor which is compatible with the one extrapolated from direct α(d, γ) 6Li experiments at relative energies above 1 MeV.