O+α experiment*

We performed alpha elastic scattering experiment with a radioactive ¹⁵O beam for investigating the structure of ¹⁹Ne near the proton threshold.  In classical novae, the intense γ-rays due to the beta decay of ¹⁸F are emitted by the HCNO cycle. The amount of ¹⁸F is determined by two destructive channels ¹⁸F(p,α)¹⁵O and ¹⁸F(p,γ)¹⁹Ne [1]. The reaction rates of the two destructive channels affect the novae calculation model [2]. For this reason, many experiments and theoretical works have been reported on the resonances of ¹⁹Ne near and above the proton threshold. However, many relevant parameters are still not measured.  The experiment was performed using the CRIB facility at the Center for Nuclear Study using the thick target method. The excitation function of ¹⁹Ne was obtained between Ex=3.53 MeV and Ex=11.13 MeV.  We also investigated the alpha cluster structure of ¹⁹Ne and compared with the recent theoretical study [3]. The experimental details and results of our study will be discussed. 

[1] M. Hernanz et al., Astrophys. J. 526, L97 (1999). 

[2] A. Coc et al., Astron. Astrophys. 357, 561(2000).

[3] R. Otani et al., Phys. Rev. C 90, 034316 (2014).