Direct measurement of astrophysical factor S(E) and screening potential for Be9(p,α)6Li reaction at low energy

As Beryllium is an important element in primary nucleosynthesis, its nuclear reaction cross-sections induced by charged projectiles need to be measured precisely. The astrophysical S(Ei) factors were measured in the ultra-low energy range from Elab=18 to 100 keV in 2-keV increments (42 points). Both the astrophysical S(E) curve (Sbare(0)=16.2±1.8MeVb) and the screening energy (Us=545±98eV) were deduced. In regard to astrophysical applications of the Sbare(E) curve, the present results are consistent with Zahnow's direct measurement. For the long-standing problem of 'abnormal' screening effect, our screening energy result also agrees with that obtained using the Trojan-horse method (Us=676±86eV) but smaller than Zahnow's value (900±50eV), although all results are much larger than that obtained in the adiabatic limit (∼264 eV).