The Anti-Coincidence Detector Subsystem for ComPair

TL;DR

The paper discusses the design, calibration, and performance evaluation of the anti-coincidence detector subsystem in the ComPair gamma-ray telescope prototype, tested during a recent balloon flight.

Contribution

It presents the first detailed design, calibration procedures, and performance metrics of the ACD subsystem in a next-generation gamma-ray detector prototype.

Findings

ACD achieved high veto efficiency during flight.

Calibration procedures improved detector accuracy.

Performance metrics met design expectations.

Abstract

ComPair is a prototype gamma-ray telescope for the development of key technologies for next-generation gamma-ray detectors consisting of four subsystems: a 10-layer double-sided silicon strip detector tracker, a cadmium zinc telluride calorimeter, a cesium iodide calorimeter, and a plastic anti-coincidence detector (ACD). The ACD acts as an active shield to veto charged particle events and consists of 5 plastic scintillating panels. ComPair was launched as a balloon payload from Ft. Sumner, New Mexico and completed a 6-hour flight on August 27, 2023. Here we detail the design adn calibration of the ComPair ACD, and report on the ACD's veto efficiency and other performance metrics during the ComPair fight.