Overview of the Nuclear Compton Telescope

Abstract

The Nuclear Compton Telescope (NCT) is a balloon-borne soft gamma-ray (0.2-10 MeV) telescope designed to study astrophysical sources of nuclear line emission and polarization. It consists of twelve high spectral resolution 3D Germanium strip detectors that track gamma-ray Compton scatter interactions with a resolution better than 2 mm 3 . Tracking technologies together with NCT's ultra-compact design provide dramatic improvements in Compton efficiency and sensitivity, achieving a similar effective area to COMPTEL with less than 1% of the detector volume. NCT will be breaking new ground in the measurement of polarized gamma-ray emission from astrophysical sources, while simultaneously providing a testing platform for novel event analysis, background reduction, and imaging techniques. Thus NCT is also serving as technology demonstration testbed for modern Compton telescopes, such as the Advanced Compton Telescope, or a focal plane detector of a gamma-ray focusing telescope. The instrument is currently being prepared for a 36-hour flight from New Mexico in Spring of 2009, followed by a long duration flight from Australia. On these science flights, NCT will map the Galactic positron annihilation, 26 Al, and 60 Fe emission, and perform a discovery study of polarization from all classes of gammaray sources. We present an overview of the NCT instrument, the planned flight program, and preliminary results of calibration and performance tests. 7th INTEGRAL Workshop