  The Advanced Compton Telescope (ACT), the next major step in gamma-ray
astronomy, will probe the fires where chemical elements are formed by enabling
high-resolution spectroscopy of nuclear emission from supernova explosions.
During the past two years, our collaboration has been undertaking a NASA
mission concept study for ACT. This study was designed to (1) transform the key
scientific objectives into specific instrument requirements, (2) to identify
the most promising technologies to meet those requirements, and (3) to design a
viable mission concept for this instrument. We present the results of this
study, including scientific goals and expected performance, mission design, and
technology recommendations.
