Experimental investigation of the ¹²C+¹²C fusion at very low energies by direct and indirect methods

The ¹²C+¹²C fusion reaction plays a crucial role during stellar evolution. The astrophysically important energy range spans from 1 MeV to 3 MeV. However, its cross section has not been determined with enough precision, despite numerous studies, due to the extremely low reaction cross sections and the large experimental background. To allow measurements of the ¹²C+¹²C fusion at astrophysical energies, we developed an efficient thick-target method using large-area silicon strip detectors. Further measurements at even lower energies will be performed using coincidences between a silicon-detector and a Ge-detector array, at the high-current accelerator under construction at the University of Notre Dame. Since the coincidence method does not allow obtaining information about the channels without gamma-ray emission, a solenoid spectrometer has been constructed for complementary measurements. Meanwhile, we are also investigating the ²⁴Mg(α, α') reaction using the Grand Raiden Spectrometer at RCNP to search for potential resonances in the ¹²C+¹²C fusion reaction. Preliminary results from these measurements will be presented.