Determination of Neutron Branching in $^{12}$C+$^{12}$C Fusion

The neutron branch of the $^{12}$C+$^{12}$C is important for the carbon shell burning and carbon explosive burning. The $^{23}$Mg created by the $^{12}$C($^{12}$C,n)$^{23}$Mg reaction may undergo $\beta^+$ decay, changing the neutron excess in the combusting material, and the neutrons emitted from this reaction may contribute to s- and r-processes. Both the $\beta^+$ decay and the neutron emission greatly affect the subsequent nucleosynthesis in the star. A detection system, consisting of an array of four plastic scintillators and two Germanium detectors, has been developed to detect the decay of the $^{23}$Mg. The system has been tested at $E_{c.m.}=4.24$MeV. Using $\beta^+ - \gamma$ coincidence technique, the $^{23}$Mg reaction products has been unambiguously identified.