The Compton Pair balloon instrument: A prototype for a next-generation gamma-ray observatory

The Compton Pair (ComPair) telescope is a prototype that aims to develop the necessary technologies for future medium energy gamma-ray missions and to design, build, and test the prototype in a gamma-ray beam and balloon flight. The ComPair team has built an instrument that consists of 4 detector subsystems: a double-sided silicon strip detector (DSSD) Tracker, a novel high-resolution Frisch-grid cadmium zinc telluride (CZT) Calorimeter, and a high-energy hodoscopic cesium iodide (CsI) Calorimeter, all of which are surrounded by a plastic scintillator anti-coincidence detector (ACD). These subsystems together detect and characterize photons via Compton scattering and pair production, enable a veto of cosmic rays, and are a proof-of-concept for a space telescope with the same architecture. A future medium-energy gamma-ray mission enabled through ComPair will address many questions posed in the recent Astro2020 Decadal survey in both the New Messengers and New Physics and the Cosmic Ecosystems themes. In this presentation we will give an overview of the ComPair project, recent analysis of the gamma-ray beam test data, and steps forward to the balloon flight.