Development of the Prototype All-sky Medium Energy Gamma-ray Observatory (AMEGO)

The electromagnetic spectrum from a few hundred keV to $>$100 MeV remains one of the most under-explored. Recent breakthroughs in multimessenger astrophysics have revealed that it is paramount in the study of sources that have unique signatures in the gamma-ray regime. The All-sky Medium Energy Gamma-ray Observatory (AMEGO) is a mission concept targeting multimessenger science in this energy range. The AMEGO instrument comprises four subsystems: a tracker, a low-energy calorimeter, a high-energy calorimeter, and a plastic scintillator anticoincidence detector. I will discuss the development of the AMEGO prototype instrument, with the ultimate goal of a balloon flight in 2021. This prototype will validate the overall instrument design under flight-like conditions and demonstrate the ability to take data in the presence of high background. In this contribution, I will discuss the current status of the prototype and preliminary results.