Low Energy Anomalies Identification in the St. George Detection System*

The St. George recoil mass separator at the University of Notre Dame is used to study the process of nucleosynthesis during the stellar helium burning phase by measuring the cross sections of alpha-capture reactions. These reactions are induced by using a beam of heavy nuclides in inverse kinematics to collide with a lighter target, for instance, the reaction 14N(α,γ)18F would have a 14N beam and a target of α particles. The St. George detection system uses a 16-pad silicon strip detector (SSD) to measure the energy of the particles and a pair of transmission detectors utilizing microchannel plates to measure the time-of-flight (TOF). Reaction products are separated from residual unreacted beam particles on a plot of TOF vs. energy. The measured energy is too low for a small number of events, and the identification is unclear. This work investigates the possibility of using hit location on the SSD, in combination with energy and TOF, to aid in identifying these low-energy events.