The S{sub E1} factor of the {sup 12}C({alpha},{gamma}){sup 16}O Reaction and the {sup 16}N {beta}-delayed {alpha} Decay

The {sup 12}C({alpha},{gamma}){sup 16}O reaction is of great importance for the understanding the nuclear synthesis and explosion mechanism of the supernova. The cross section at the relevant stellar burning energies, around 300 keV, is dominated by the sub-threshold resonances. The {sup 16}N {beta}-delayed {alpha} decay data provide the most sensitive constrain on this sub-threshold resonance. Using twin-ionization chambers, we have measured the {alpha} particles and {sup 12}C recoil nuclei in coincidence. The spectrum has been fitted together with the published {sup 12}C({alpha},{gamma}){sup 16}O data and the elastic scattering phase shift data using R-matrix. The S{sub E1} factor at 300 keV has been determined as 73{+-}21 keVb.