AMEGO-X is a MIDEX mission concept that is based largely on Fermi-LAT heritage but is optimized for the MeV range.
The instrument is composed of three subsystems: a Silicon Tracker, a Cesium Iodide (CsI) calorimeter, and an anti-coincidence detector (ACD).
The Tracker and Calorimeter work together to detect photons which undergo Compton scattering and pair conversion in the detector volume,
allowing for a photon-by-photon reconstruction, while the ACD vetos the background from charge particles.