Simulation of the Focal Plane Detection Systems for the study of the 12C(a,g)16O Reaction with St. George Recoil Separator

The 12C(a,g)16O reaction is one of the most important reactions in nuclear astrophysics. The lowest energy we have reached is limited by the background in the detectors. To reduce the background, the St. George recoil separator is designed to study the radiative capture reactions with inverse kinematics. One key instrument of the recoil separator is the detection system at the focal plane used to identify the 16O reaction products from the 12C leakage through the recoil separator. Several focal plane detection systems were simulated with SRIM-2006 to determine the optimal conditions for particle identification. These simulations include a time of flight (TOF) and gas ionization chamber (GIC) configuration, as well as a double TOF configuration. Based on the simulation, the best detection solutions are recommended. Non-uniformities in the entrance window of the GIC and in the energy degrader of the double TOF system were also explored, and affect particle identification greatly, suggesting the necessity of tracking components to correct for large scale non-uniformities.