The 18O(p, α)15N reaction at stellar energies

doi:10.1016/0375-9474(79)90505-0

Nuclear Physics A

Volume 313, Issue 3, 22 January 1979, Pages 346-362

https://doi.org/10.1016/0375-9474(79)90505-0 Get rights and content

Abstract

The ¹⁸O(p, α)¹⁵N reaction has been investigated in the energy range E_p = 72–935 keV. The three known resonances above E_p = 620 keV have been confirmed and four new resonances have been found below E_p = 340 keV. All observed resonances correspond to known compound states in ¹⁹F. Information on resonance energies, total widths and ωγ values is reported. The low-energy resonances are superimposed on a non-resonant reaction yield, which varies smoothly with beam energy and which exhibits pronounced α-particle angular distributions asymmetric around 90°. The explanation of these data requires either interferring amplitudes of broad resonances with differing parities or a direct (p, α) reaction mechanism. The investigated energy range corresponds to the important temperature range of T = (0.05–2.5) × 10⁹ K. The energy averaged astrophysical reaction rates are compared with predictions.

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Improved astrophysical rate for the <sup>18</sup>O(p,α)<sup>15</sup>N reaction by underground measurements
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Citation Excerpt :
Furthermore, the 0.3 keV uncertainty in the energy of each data point of this work was converted into an uncertainty in the corresponding cross-section and added in quadrature to the other statistical uncertainties. The authors acknowledge A.I. Karakas for providing the stellar structure of the 5 M⊙ Monash model, and R.J. deBoer for a digitization of data from [11]. This work was supported in part by INFN, STFC UK (grant no. ST/L005824/1), NKFIH (grant no. K120666), HAS Lendület (grant no. LP2014-17), and DFG (grant no. BE 4100/4-1).
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The simulated two-dimensional histogram of the energy deposited in the HPGe detector (x-axis) versus the energy deposited in the NaI(Tl) annulus (y-axis) is shown in Fig. 7. The known decay scheme and Q-value are taken from Refs. [12–16] and are built into the simulation. Fig. 8 shows the comparison between the data and simulation with the condition for Gate 1 applied.
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^☆: Supported in part by the Deutsche Forschungsgemeinschaft [Ro 429/2-5].

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The 18O(p, α)15N reaction at stellar energies☆

Abstract

Ann. Rev. Astr. and Astrophys.

Nucl. Data Tables

Thin Solid Films

Nucl. Phys.

Astrophys. J. Lett.

Nucl. Phys.

Nucl. Phys.

J. of Phys.

Phil. Mag.

Phil. Mag.

The ¹⁸O(p, α)¹⁵N reaction at stellar energies☆