Lithium isotopes have attracted an intense interest because the abundance of both 6Li and 6Li from big bang nucleosynthesis (BBN) is one of the puzzles in nuclear astrophysics. Many investigations of both astrophysical observation and nucleosynthesis calculation have been carried out to solve the puzzle, but it is not solved yet. Several nuclear reactions involving lithium have been indirectly measured at China Institute of Atomic Energy, Beijing. The Standard BBN (SBBN) network calculations are then performed to investigate the primordial Lithium abundance. The result shows that these nuclear reactions have minimal effect on the SBBN abundances of 6Li and 7Li.
LI ZhiHong1, LI ErTao1, SU Jun1, LI YunJu1, BAI XiXiang1, GUO Bing1, WANG YouBao1, CHEN YongShou1, HOU SuQing1, ZENG Sheng1, LIAN Gang1, SHI JianRong2 & LIU WeiPing1 1 China Institute of Atomic Energy, Beijing 102413, China
The angular distribution of the 12C(7Li,6He)13N reaction at E(7Li) = 44.0 MeV was measured at the HI-13 tandem accelerator of Beijing, China. The asymptotic normalization coefficient (ANC) of 13N → 12C + p was derived to be (1.64 ± 0.11) fm-1/2 through the distorted wave Born approximation (DWBA) analysis. The ANC was then used to deduce the astrophysical S (E) factors and reaction rates for the 12C(p,γ)13N direct capture reaction at energies of astrophysical relevance.
LI ZhiHong, SU Jun, GUO Bing, LI ZhiChang, BAI XiXiang, LIU JianCheng, LI YunJu, YAN ShengQuan, WANG BaoXiang, WANG YouBao, LIAN Gang, ZENG Sheng, LI ErTao, CHEN YongShou, SHU NengChuan, FAN QiWen & LIU WeiPing China Institute of Atomic Energy, Beijing 102413, China
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.
Angular distributions for the ~7(Li)(~6(Li),~7(Li))~6(Li) Li elastic-transfer reaction have been measured with the Q3D magnetic spectrograph at the HI-13 tandem accelerator of Beijing, China. The neutron spectroscopic factors of 7Li are derived by comparing the calculated differential cross sections, which are obtained through the distorted-wave Born approximation (DWBA) calculation, to the experimental data. And these spectroscopic factors are then used to deduce the direct capture cross sections in 6Li(n,γ)7 Li at energies of astrophysical relevance.
The School of Nuclear Engineering and Technology at the East China Institute of Technology cooperated with the China Institute of Atomic Energy to investigate the high spin states of 84Sr. The study is reported in Volume 53 (October, 2010) of the SCIENCE
The 13C(7Li, 6He) 14N reaction is measured at E(7Li) = 34 MeV with the Q3D magnetic spectrometer of HI-13 tandem accelerator. Angular distributions at forward angles for proton transfer to the ground and the first excited states in 14N are obtained. In addition, angular distribution for 7Li + 13 C elastic scattering is also measured. The optical potential parameters for the entrance and exit channels of the transfer reactions are derived by fitting the 7Li + 13C and 6Li + 14N elastic scattering experimental data, and their angular distributions are well reproduced by the distorted wave Born approximation calculations. A phase shift of about 2 between the calculations and the experiment data has been found in the earlier (7Li, 6He) study, whereas no such phase shift is observed in the present work.
