Measurement of the E1 and E2 partial cross sections of the C(,)O reaction at E = 1.2 and 1.5 MeV using pulsed beam

Makii, Hiroyuki   ; Ueda, Hitoshi*; Nagai, Yasuki*; Segawa, Mariko   ; Temma, Yasuyuki*; Shima, Tatsushi*; Mishima, Kenji*; Igashira, Masayuki*

The C(,)O reaction plays an important role in stellar evolution at the stage of He-burning. However the cross section at the stellar temperature still has a large uncertainty mainly due to the poor determination of the cross section ratio, . In order to make a precise measurement of the , we have installed a new measurement system of the -ray angular distributions of the C(,)O reaction. In this experiment, we used high efficiency anti-Compton NaI(Tl) spectrometers to detect -rays from the reaction with a large S/N ratio, an intense pulsed beams, and the monitoring system of the target thickness. With use of the system we succeeded in removing a background due to neutrons and could clearly detect the -ray from the reaction with high statistics. We determined the E1 and E2 cross section down to E = 1.2 MeV, and thus obtained results are compared to recent theoretical calculations.