Direct measurement of 4He(12C, 16O)γ reaction cross section around Ecm=2.4 MeV at KUTL

A direct measurement of He-4(C-12, O-16)gamma reaction cross section is in progress at Kyushu University tandem laboratory (KUTL). A C-12 beam is incident on a windowless He-4 gas target. The O-16 recoils are separated from the beam by a recoil mass separator and are detected by a Si-detector. In order to increase beam intensity, target thickness and detection efficiency, original instruments and methods have been newly developed. To reduce background (BG), a beam from the tandem accelerator was pulsed. Recently a long-time chopper was developed to further separate the reaction recoils and BG, and a test measurement of He-4(C-12, O-16)gamma reaction cross section at E-cm = 2.4 MeV was made.