Direct Measurement of the 4He(12C, 16O)γ Total Cross Section Near Stellar Energies

Abstract

A cross section measurement employing a direct 16O detection method for the reaction energies from Ecm = 2.4 to 0.7 MeV is planned at Kyushu University Tandem Laboratory (KUTL). To perform this experiment and to obtain quantitative information about the cross section to within an error of 10%, we have developed several instruments, including a blow-in type windowless gas target, a recoil mass separator and a RF-deflector. The measurements at Ecm = 2.4 and 1.5 MeV have been performed with these instruments. For measuring at Ecm < 1.2 MeV, a hybrid detector employing both, an ionization chamber and a silicon detector was developed to reduce the carbon backgrounds more efficiently. The oxygen ions were clearly separated from carbon background by using the energy deposit in the ionization chamber. Experiment of Ecm = 1.2 MeV was performed and the cross section was obtained.