A new study for 16O(γ,α)12CO(γ,α)12C at the energies of nuclear astrophysics interest: The inverse of key nucleosynthesis reaction 12C(α,γ)16OC(α,γ)16O

The key reaction 12C(α,γ)16OC(α,γ)16O in nuclear astrophysics is difficult to be performed experimentally at low energy because of the Coulomb barrier. But it is different if we use its inverse reaction 16O(γ,α)12CO(γ,α)12C because the cross-section of 16O(γ,α)12CO(γ,α)12C is almost 100 times larger than the cross-section of 12C(α,γ)16OC(α,γ)16O at the same center of mass energy (Ec.m.)(Ec.m.) based on our study. In the present work, we study the angular distributions and total cross-sections of 16O(γ,α)12CO(γ,α)12C which are induced by polarized photon using the resonance theory of low energy reaction. The differential cross-sections as well as E1 and E2 transition cross-sections at low nuclear astrophysics energies are also calculated. The feature of the future Shanghai Laser Electron Gamma Source (SLEGS) facility, a low energy γγ-ray beam line with a high photon flux, is presented. The experiments of 16O(γ,α)12CO(γ,α)12C are simulated with a time projection chamber (TPC) and a realistic SLEGS layout. The lowest (Ec.m.)(Ec.m.), which can be obtained from the simulation, is 0.8 MeV with the 20–30% uncertainty for the one-month beam time of SLEGS. The extracted SS factors of 12C(α,γ)16OC(α,γ)16O and their statistical uncertainties from the simulation are compared with the existing data and some theoretical calculations. It is shown that the promising 16O(γ,α)12CO(γ,α)12C experiment at SLEGS can largely reduce the statistical uncertainties of the 12C(α,γ)16OC(α,γ)16O experiment at low energies.