ComPair, the prototype of the All-sky Medium Energy Gamma-ray Observatory (AMEGO) mission concept, is a combined Compton imager and pair production telescope. It consists of four subsystems: a double-sided silicon strip detector (DSSD) Tracker, a virtual Frisch-grid cadmium zinc telluride (CZT) Low Energy Calorimeter, a cesium iodide (CsI) High Energy Calorimeter, and a plastic scintillator Anti-Coincidence Detector (ACD) to reject the charged particle background. These subsystems work together to reconstruct events, by tracking the locations and energies of gamma-ray scatters and pair production events. To quantify ComPair's scientific capabilities prior to a balloon launch in 2023, calibrations were performed to benchmark the instrument's performance in terms of angular resolution, energy resolution, and effective area. In this paper we provide an overview of the ComPair instrument and detail the calibration campaign. Finally, we compare our results to the expected performance based on simulations.
@article{arxiv.2510.12938,
title = {Calibration of the ComPair Balloon Instrument},
author = {Nicholas Kirschner and Zachary Metzler and Lucas D. Smith and Carolyn Kierans and Regina Caputo and Nicholas Cannady and Makoto Sasaki and Daniel Shy and Priyarshini Ghosh and Sean Griffin and J. Eric Grove and Elizabeth Hays and Iker Liceaga-Indart and Emily Kong and Julie McEnery and John Mitchell and A. A. Moiseev and Lucas Parker and Jeremy S. Perkins and Bernard Phlips and Adam J. Schoenwald and Clio Sleator and Jacob Smith and Janeth Valverde and Sambid Wasti and Richard Woolf and Eric Wulf and Anna Zajczyk},
journal= {arXiv preprint arXiv:2510.12938},
year = {2025}
}