Calibration of the anti-coincidence detector subsystem for the Compton Pair balloon instrument

The Compton Pair (ComPair) balloon instrument is a prototype gamma-ray telescope for the development of key technologies for next-generation gamma-ray detectors. ComPair consists of four subsystems: a double sided silicon strip tracker, a cadmium zinc telluride calorimeter, a cesium iodide calorimeter, and a plastic anti-coincidence detector (ACD). The ACD consists of 5 plastic scintillating panels, each optically coupled to 2 wavelength shifting (WLS) bars. Each WLS bar is read out with a 2x2 silicon photomultiplier (SiPM) array. In this presentation, we will describe the latest ComPair ACD design and share the latest analysis of the energy and position calibration of the ACD using cosmic muons and gamma ray sources.