通过\(^{12}C(\alpha,\gamma)^{16}O\)反应中\(^{16}O\)的第一激发态测量级联跃迁及其在恒星氦燃烧中的S因子。
Measurement of the cascade transition via the first excited state of 16O in the 12C(alpha,gamma)16O reaction, and its S factor in stellar helium burning.
作者信息
Matei C, Buchmann L, Hannes W R, Hutcheon D A, Ruiz C, Brune C R, Caggiano J, Chen A A, D'Auria J, Laird A, Lamey M, Li Z H, Liu W P, Olin A, Ottewell D, Pearson J, Ruprecht G, Trinczek M, Vockenhuber C, Wrede C
机构信息
Ohio University, Athens, Ohio, USA.
出版信息
Phys Rev Lett. 2006 Dec 15;97(24):242503. doi: 10.1103/PhysRevLett.97.242503.
Radiative alpha-particle capture into the first excited, J(pi)=0+ state of 16O at 6.049 MeV excitation energy has rarely been discussed as contributing to the 12C(alpha,gamma)16O reaction cross section due to experimental difficulties in observing this transition. We report here measurements of this radiative capture in 12C(alpha,gamma)16O for center-of-mass energies of E=2.22 MeV to 5.42 MeV at the DRAGON recoil separator. To determine cross sections, the acceptance of the recoil separator has been simulated in GEANT as well as measured directly. The transition strength between resonances has been identified in R-matrix fits as resulting both from E2 contributions as well as E1 radiative capture. Details of the extrapolation of the total cross section to low energies are then discussed [S6.0(300)=25(-15)(+16) keV b] showing that this transition is likely the most important cascade contribution for 12C(alpha,gamma)16O.
由于观测这一跃迁存在实验困难，将辐射α粒子俘获到激发能为6.049 MeV的16O的第一激发态J(π)=0+，很少被讨论为对12C(α,γ)16O反应截面有贡献。我们在此报告在DRAGON反冲分离器上对质心能量E = 2.22 MeV至5.42 MeV的12C(α,γ)16O中这种辐射俘获的测量。为了确定截面，反冲分离器的接受度已在GEANT中进行了模拟，并直接进行了测量。在R矩阵拟合中，共振之间的跃迁强度已被确定为既来自E2贡献，也来自E1辐射俘获。然后讨论了将总截面外推到低能的细节[S6.0(300)=25(-15)(+16) keV b]，表明这种跃迁可能是12C(α,γ)16O最重要的级联贡献。
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