Cross sections and reaction rates for 23Na(p,n) 23Mg, 27Al(p,n) 27Si, 27Al(α,n) 30P, 29Si(α,n) 32S, and 30Si(α,n) 33S

The total neutron production cross sections for the 23Na(p,n)23Mg, 27Al(p,n)27Si, 27Al(α,n)30P, 29Si(α,n)32S, and 30Si(α,n)33S reactions have been measured for bombarding energies from threshold to 6.3 MeV. The neutron detector was a 60-cm diameter sphere of polyethylene with eight 10BF3 counters and was insensitive to the angle and energy of the emitted neutrons. Cross sections for inverse reactions have been obtained using the principle of detailed balance. The data have been used to determine parameters for statistical model calculations to facilitate extrapolation of cross sections to higher bombarding energies. These reactions are relevant to problems of nucleosynthesis and stellar evolution and to studies of radiation damage. Nucleosynthesis reaction rates, N/sub A/(sigmav), were determined for the reactions studied and are tabulated for temperatures ranging from 0.4 x 109 to 10.0 x 109 K