Measurement system of the γ-ray angular distributions of the C(α,γ)12O16 reaction

A new system to measure the γ-ray angular distributions of the C(α,γ)12O16 reaction has been installed at the 3.2 MV Pelletron accelerator laboratory at Tokyo Institute of Technology. An intense 2.27 MeV α-beam with the pulse width of 1.9 ns was used to study the performance of the system. The γ-rays from the C(α,γ)12O16 reaction were detected with three high-efficiency anti-Compton NaI(Tl) spectrometers, and they were well separated from neutron background from the C(α,n)13O16 reaction using a time of flight method. The present study has demonstrated high sensitivity of the system to measure the γ-ray angular distributions of the C(α,γ)12O16 reaction at low energy, and to determine both E1 and E2 cross-sections.