E1 and E2 cross sections of the 12C(α,γ0)16O reaction using pulsed α beams
E1 and E2 cross sections of the 12C(α,γ0)16O reaction using pulsed α beams
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DOI：
10.1103/physrevc.80.065802
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发表时间：
2009-12-01
影响因子：
3.1
通讯作者：
Ohsaki, T.
中科院分区：
文献类型：
--
作者：
Makii, H.;Nagai, Y.;Ohsaki, T.
我们用E-eff=1.6和1.4 MeV的脉冲α束测量了C-12（alpha，gamma（0））O-16到O-16基态的γ射线角分布。由于C-13（alpha，n）O-16的中子，用飞行时间方法将C-12（alpha，gamma（0））O-16的真实事件与背景事件区分开来。用反康普顿NaI（TI）光谱仪获得的γ射线光谱显示出C-12（alpha，gamma（0））O-16的特征线形：C-12靶中α粒子的多普勒增宽和能量损失。在束辐照过程中测量了富集C-12靶的α粒子卢瑟福背散射谱，以获得靶厚度和入射α束强度。由本截面导出的E1和E2的天体物理S因子S-E1（gamma（0）：E-eff）和S-E2（gamma（0）：E-eff）与N-16的β延迟α谱的R矩阵计算值以及在R矩阵拟合中使用渐近归一化常数得到的值非常一致。
We measured the gamma-ray angular distribution from C-12(alpha,gamma(0))O-16 to the ground state of O-16 using a pulsed alpha beam at E-eff=1.6 and 1.4 MeV. True events of C-12(alpha,gamma(0))O-16 were discriminated from background events with a time-of-flight method because of neutrons from C-13(alpha,n)O-16. The obtained gamma-ray spectrum with anti-Compton NaI(Tl) spectrometers showed a characteristic line shape from C-12(alpha,gamma(0))O-16: the Doppler broadening and energy loss of alpha particles in C-12 targets. A Rutherford backscattering spectrum of alpha particles from enriched C-12 targets was measured during beam irradiation to obtain the target thickness and incident alpha-beam intensities. The astrophysical S factors for E1 and E2,S-E1(gamma(0):E-eff) and S-E2(gamma(0):E-eff), derived from the present cross sections are in excellent agreement with the values derived by R-matrix calculation of the beta-delayed alpha spectrum of N-16, and by using the asymptotic normalization constant in the R-matrix fit.