Measurement system of the -ray angular distributions of the reaction

A new system to measure the γ -ray angular distributions of the C ( α , γ ) 12 O 16 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 ) 12 O 16 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 ) 13 O 16 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 ) 12 O 16 reaction at low energy, and to determine both E1 and E2 cross-sections.