Baoxiang Wang

Current progress of nuclear astrophysics study and BRNBF at CIAE

Abstract A secondary beam line (GIRAFFE) at the Beijing tandem accelerator lab was constructed for yielding low energy secondary beams. The current progress on the study of nuclear astrophysics and nuclear structure is presented. Up to now, we have carried out measurement of 7 Be(d,n) 8 B, 11 C(d,n) 12 N, 8 Li(d,n) 9 Be and 6 He(p,n) 6 Li reactions. The proposed Beijing radioactive nuclear beam facility and its current R&D progress are briefly introduced. This facility is based on the exist HI-13 tandem accelerator. A proton cyclotron will be built to provide 100 MeV 200 μA proton beam, together with an isotope separator on line system and a super-conducting heavy ion LINAC. By this facility, intensity of order of 10 9 pps radioactive nuclear beams for mass up to A =120 will be produced.

INDIRECT MEASUREMENTS OF NUCLEAR ASTROPHYSICS REACTIONS USING UNSTABLE NUCLEAR BEAMS

This paper described the nuclear astrophysical studies using the unstable ion beam facility GIRAFFE, by indirect measurements. We measured the angular distributions for some single proton or neutron transfer reactions, such as 7Be(d,n)8B, 11C(d,n)12N, 8Li(d,n)9Be, 8Li(d,p)9Li and 13N(d,n)14O in inverse kinematics, and derived the astrophysical S-factors or reaction rates of 7Be(p,γ)8B, 11C(p,γ)12N, 8Li(n,γ)9Li, 13N(p,γ)14O by asymptotic normalization coefficient, spectroscopic factor, and R-matrix approach at astrophysically relevant energies.

Nuclear Astrophysics Experiments at CIAE

This paper describes the nuclear astrophysical studies using the unstable ion beam facility, GIRAFFE.We measured the angular distributions for some low energy reactions, such as 7Be(d,n)8B, 11C(d,n)12N, 8Li(d,n)9Be, 8Li(d,p)9Li and 17F(d,n)18Ne in inverse kinematics, and derived the astrophysical S‐factors or reaction rates of 7Be(p,γ)8B, 11C(p,γ)12N, 8Li(n,γ)9Li, 17F(p,γ)18Ne by asymptotic normalization coefficient approach at astrophyscally relevant energies.

Experimental studies on the primordial lithium abundance

Lithium isotopes have attracted an intense interest because the abundances of both 6Li and 7Li from big bang nucleosynthesis (BBN) are the puzzles in nuclear astrophysics. Many investigations of astrophysical observation and BBN calculations have been carried out in order to solve the puzzles. Several nuclear reactions involving lithium have been determined at HI-13 tandem accelerator, Beijing, China. The BBN model calculations are then performed to investigate the primordial Lithium abundance. The result shows that these nuclear reactions have minimal effect on the primordial abundances of 6Li and 7Li.

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.

Current progress of nuclear astrophysics experiments at CIAE

This paper described current progress of nuclear astrophysical studies using the unstable ion beam facility GIRAFFE. We measured the angular distributions for some low energy reactions, such as 11C(d,n)12N, 8Li(d,p)9Li and 17F(d,n)18Ne in inverse kinematics, and indirectly derived the astrophysical S‐factors or reaction rates of 11C(p,γ)12N, 8Li(n,γ)9Li, 8B(p,γ)9C at astrophysically relevant energies.

Determination of the astrophysical 8Li(n, γ)9Li reaction rate from the measurement of 2H(8Li,9 Li)1H reaction

The cross section of the 8Li(n, γ)9Li reaction has attracted much attention for many years because of its importance in nuclear astrophysics. The single particle spectroscopic factor, S1,3/2 for the ground state of 9Li = 8Li ⊗ n derived from the transfer reaction of 8Li(d, p)9Li was used to calculate the direct radiative capture reaction rates of 8Li(n, γ)9Li at energies of astrophysical interest. The present result shows that the 8Li(n, γ)9Li direct capture reaction may play an important role in the astrophysical environments of inhomogeneous big bang and type II supernovae.

Indirect measurements of nuclear astrophysics reactions at CIAE

This paper described the nuclear astrophysical studies using the unstable ion beam facility GIRAFFE, by indirect measurements. We measured the angular distributions for some single proton or neutron transfer reactions, such as 7Be(d,n)8B, 11C(d,n)12N, 8Li(d,n)9Be, 8Li(d,p)9Li and 13N(d,n)14O in inverse kinematics, and derived the astrophysical S‐factors or reaction rates of 7Be(p,γ)8B, 11C(p,γ)12N, 8Li(n,γ)9Li, 13N(p,γ)14O by asymptotic normalization coefficient, spectroscopic factor, and R‐matrix approach at astrophysically relevant energies.