A windowless gas target for low-energy He (C, O) γ experiment: improvement to reduce O backgrounds.

A blow-in type windowless thick He gas target has been developed to measure He(C,O) γ cross section for astrophysical interests. We use a C beam of energy from 6 to 2.8 MeV and detect O recoils at forward angles. Numerous C backgrounds have been rejected by particle identification techniques. O backgrounds from the target are not many but fatally harmful. Our techniques to reduce the O backgrounds are described. [ABSTRACT FROM AUTHOR]