Zhichang Li

Measurement of the Angular distribution for the 7Be(d, n)8B reaction and determination of the astrophysical S factor for the 7Be(p, γ)8B reaction

Abstract The differential cross section for the 7Be(d, n)8B reaction at Ec.m.=5.8 MeV has been measured using a 7Be beam produced by the radioactive nuclear beam facility at the China Institute of Atomic Energy. The 8B ions were detected in full geometry with a two dimensional position sensitive ΔE-E counter telescope. The reaction cross section was determined to be 58±8 mb. The angular distribution data were analyzed with a distorted-wave Born approximation calculation. The astrophysical S17(0) factor for the 7Be(p, γ)8B reaction was derived to be 27.4±4.4 eV b through the asymptotic normalization constant extracted from the experimental data.

Neutron halo state of13C

Angular distributions for the12C(d, p)13C transfer reactions have been measured at Ed = 11.8 MeV, and compared with those of the DWBA calculations. By means of this comparison, density distributions of the last neutron in the ground state and the first 1/2+ state of13C are extracted. The properties of these states in13C have also been studied in the framework of the nonlinear relativistic mean-field theory with NL-SH parameters. It is found that the first 1/2+ state in13C is a neutron halo state shown by both the experimental and theoretical density distributions of the last neutron.

Indirect Measurement of Astrophysical13C(α, n)16OS-Factors

The 13C(α, n)16O reaction is believed to be the main neutron source reaction for the s-process in asymptotic giant branch (AGB) stars. The astrophysical S-factors of this reaction have been determined based on an evaluation of the α spectroscopic factor of the 1/2+ subthreshold state in 17O (Ex = 6.356 MeV) by using the 13C(11B, 7Li)17O α transfer reaction. Our result confirms that the 1/2+ subthreshold resonance is dominant for the 13C(α, n)16O reaction at low energies of astrophysical interest.