原子能院的核天体物理研究和串列升级工程进展(英文)

在北京串列实验室建立了次级束流实验装置 ,用于放射性核束物理和核天体物理研究 .先后开展了7Be(d ,n) 8B ,11C(d ,n) 12 N ,8Li(d ,p) 9Li和6 He(p ,n) 6 Li核天体物理重要反应的研究 .介绍了串列加速器升级工程的进展情况 .该工程在现有串列加速器的基础上 ,将建立 10 0MeV/ 2 0 0 μA的质子回旋加速器、在线同位素分离器和超导加速段 .在此装置上 ,将可以产生质量数最高为 12 0 ,强度最高为 10 9particles/s的放射性束流 . 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, p)~(9)Li, and~(6)He(p, n)~(6)Li reactions. The proposed Beijing radioactive nuclear beam facility (BRIF ) and its current R&D progress are briefly introduced. This facility is based on...     

Angular Distribution of the 12C（6He, 7Li）nB Reaction

Angular distribution of the 12C（6He, 7Li）llB transfer reaction is measured with a secondary 6He beam of 36.4 MeV for the first time. The experimental angular distribution is well reproduced by the distorted-wave Born approxima- tion （DWBA） calculation. The success of the present experiment shows that it is feasible to measure one-nucleon transfer reaction on a light nucleus target with the secondary beam facility of the 1-11-13 tandem accelerator at China Institute of Atomic Energy （CIAE）, Beijing.     

Enhancement of β^＋-Decay Rate of ^22Na in Metal Pd at Low Temperature

Temperature dependence of nuclear decays in metallic environments is a controversial issue. We measured the temperature dependence of the β^＋-decay half-life of ^22Na implanted into the metal host of palladium. It is found that the β^＋-decay half-life of ^22Na in the metal Pd cooled to T = 15 K is shorter by 0.46（14）% than that at room temperature. The result is consistent in sign with, but dearly smaller than, the estimated one by the Debye model.     

Monopole effects and high-spin levels in neutron-rich 132Te

The neutron-rich nuclei near doubly magic ¹³²Sn have attracted considerable interest in both nuclear physics and nuclear astrophysics. For the particle-hole nuclei in this region, the low-lying and high core excitations have been well described by shell model calculations using the extended pairing plus multipole-multipole force model. However, there is a significant difference between experiment and theory in the high-spin level 17⁺ of ¹³²Te. We intend to illust...     

Levels in 13N examined by 12C+p elastic resonance scattering with thick target

The elastic resonance scattering of ¹²C+p has been studied in inverse     

10Be中子谱因子的实验研究

核谱因子描述了单粒子轨道中核子的占有状态,在核结构和核天体物理中有重要的应用。目前国际上10Be中子谱因子的研究结果存在3倍左右的差异。本实验利用中国原子能科学研究院HI-13串列加速器的高灵敏度Q3D磁谱仪,对13C（9Be,10Be）12C反应角分布进行了精确测量。通过实验数据和扭曲波玻恩近似（DWBA）计算结果进行比较,导出了10Be的中子谱因子。该结果与转动不变壳模型理论及曾敏尔等的评价结果基本一致。利用该结果可以得到9Be（n,γ）10Be的天体物理反应率,评价该反应在相关天体环境中对CNO循环种子核12C的影响,为核结构和核天体物理提供可靠数据。Spectroscopic factor describes the overlap between the initial and final states and gives some information on the occupancy of a given single-particle orbiting around nuclear. It plays an important role in a variety of topics on nuclear structure and nuclear astrophysics. Nowadays, several experiments have been performed to study the neutron spectroscopic factor of 10Be, but the results have a big difference with each other. In order to clarify this discrepancy, new measurement is highly needed. In this work, the angular distribution of 13C(9Be,10Be)12C reaction was measured at the Q3D magnetic spectrometer of the HI-13 tandem accelerator, China Institute of Atomic Energy, Beijing. And then, the neutron spectroscopic factor of 10Be was derived by normalizing the calculational differential cross-sections with the distorted-wave Born approximation to the experimental data. The present value is in good agreement with that obtained by Tsang et al. and also in good agreement with that derived from translationary invariant shell model calculation. One can use this result to calculate the 9Be(n, γ)10Be reaction rates and calculate its influence to the production of 12C.