The ^7Be（p, γ）8B reaction plays a central role not only in the evaluation of solar neutrino fluxes but also in the evolution of the first stars. Study of this reaction requires the asymptotic normalization coeffici...The ^7Be（p, γ）8B reaction plays a central role not only in the evaluation of solar neutrino fluxes but also in the evolution of the first stars. Study of this reaction requires the asymptotic normalization coefficient （ANC） for the virtual decay ^8Bg.s. → ^7Be ＋ p. By using the charge symmetry relation, we obtain this proton ANC with the single neutron ANC of ^8Lig.s.→^7Li ＋ n, which is determined with the distorted wave Born approximation （DWBA） and adiabatic distorted wave approximation （ADWA） analysis of the ^7Li（d, p）^8Li angular distribution. The astrophysical S-factors and reaction rates of the direct capture process in the 7Be（p, y）SB reaction are further deduced at energies of astrophysical relevance. The astrophysical S-factor at zero energy for direct capture, S 17（0）, is derived to be （19.9 ± 3.5） eV b in good agreement with the most recent recommended value. The contributions of the 1 ^＋ and 3^＋ resonances to the S-factor and reaction rate are also evaluated. The present result demonstrates that the direct capture dominates the ^7Be（p, γ）8B reaction in the whole temperature range. This work provides an independent examination to the current results of the ^7Be（p, γ）8B reaction.展开更多
The cross-section data of the 85Rb(n,2 n)84Rb reaction have been measured with the neutron energies of 12 MeV to 19.8 MeV using the activation technique and the relative method.The 85Rb samples were irradiated on the ...The cross-section data of the 85Rb(n,2 n)84Rb reaction have been measured with the neutron energies of 12 MeV to 19.8 MeV using the activation technique and the relative method.The 85Rb samples were irradiated on the surface of a two-ring orientation assembly with neutrons produced from the 3H(d,n)4He reaction at the 5SDH-21.7-MV Tandem accelerator in China.Theoretical model calculations were performed with the TALYS-1.9 code.The present data were compared with previously obtained experimental data and the available evaluated data.展开更多
The cross sections of the^(169)Tm(n,2n)^(168)Tm reaction have been measured at incident energies of 12 to 19.8 MeV using the activation technique,relative to the^(93)Nb(n,2n)^(92)mNb reaction.Thulium(Tm)samples were i...The cross sections of the^(169)Tm(n,2n)^(168)Tm reaction have been measured at incident energies of 12 to 19.8 MeV using the activation technique,relative to the^(93)Nb(n,2n)^(92)mNb reaction.Thulium(Tm)samples were irradiated on the surface of a two-ring orientation assembly with neutrons produced from the^(3)H(d,n)^(4)He reaction at the 5SDH-21.7-MV Tandem accelerator in China.Theoretical model calculations were performed.The present data were then compared with previous experimental data and available evaluated data.This study provides more precise nuclear data for improvement of future evaluations.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11321064,11490560,11475264,11375269 and11275272)the National Basic Research Program of China(Grant No.2013CB834406)
文摘The ^7Be（p, γ）8B reaction plays a central role not only in the evaluation of solar neutrino fluxes but also in the evolution of the first stars. Study of this reaction requires the asymptotic normalization coefficient （ANC） for the virtual decay ^8Bg.s. → ^7Be ＋ p. By using the charge symmetry relation, we obtain this proton ANC with the single neutron ANC of ^8Lig.s.→^7Li ＋ n, which is determined with the distorted wave Born approximation （DWBA） and adiabatic distorted wave approximation （ADWA） analysis of the ^7Li（d, p）^8Li angular distribution. The astrophysical S-factors and reaction rates of the direct capture process in the 7Be（p, y）SB reaction are further deduced at energies of astrophysical relevance. The astrophysical S-factor at zero energy for direct capture, S 17（0）, is derived to be （19.9 ± 3.5） eV b in good agreement with the most recent recommended value. The contributions of the 1 ^＋ and 3^＋ resonances to the S-factor and reaction rate are also evaluated. The present result demonstrates that the direct capture dominates the ^7Be（p, γ）8B reaction in the whole temperature range. This work provides an independent examination to the current results of the ^7Be（p, γ）8B reaction.
基金Supported by National Natural Science Foundation of China(11575163)
文摘The cross-section data of the 85Rb(n,2 n)84Rb reaction have been measured with the neutron energies of 12 MeV to 19.8 MeV using the activation technique and the relative method.The 85Rb samples were irradiated on the surface of a two-ring orientation assembly with neutrons produced from the 3H(d,n)4He reaction at the 5SDH-21.7-MV Tandem accelerator in China.Theoretical model calculations were performed with the TALYS-1.9 code.The present data were compared with previously obtained experimental data and the available evaluated data.
基金Supported by the National Natural Science Foundation of China(12075216)。
文摘The cross sections of the^(169)Tm(n,2n)^(168)Tm reaction have been measured at incident energies of 12 to 19.8 MeV using the activation technique,relative to the^(93)Nb(n,2n)^(92)mNb reaction.Thulium(Tm)samples were irradiated on the surface of a two-ring orientation assembly with neutrons produced from the^(3)H(d,n)^(4)He reaction at the 5SDH-21.7-MV Tandem accelerator in China.Theoretical model calculations were performed.The present data were then compared with previous experimental data and available evaluated data.This study provides more precise nuclear data for improvement of future evaluations.
