The Nuclear Compton Telescope (NCT): Scientific goals and expected sensitivity

The Nuclear Compton Telescope (NCT) is a balloon-borne telescope designed to study astrophysical sources of gamma-ray emission with high spectral resolution, moderate angular resolution, and novel sensitivity to gamma-ray polarization. The heart of NCT is an array of cross-strip germanium detectors, each of 15-mm thickness and 5400 mm2 active area, with full 3D position resolution <2 mm3. NCT will perform Compton imaging in the 0.2–10 MeV gamma-ray band. We are currently planning a 12-detector long duration balloon flight of the NCT instrument from Australia in December 2008. NCT is the prototype of a future satellite mission, which will have a coded mask on top of a larger detector array to carry out imaging in the 20–100 keV X-ray band. This paper describes the scientific goals, as well as the detector design, simulated performance and current status of the project. NCT is a joint effort of several institutions in the US and in Taiwan.