PANGU: a wide field gamma-ray imager and polarimeter

PANGU (the PAir-productioN Gamma-ray Unit) is a gamma-ray telescope with a wide field of view optimized for spectro-imaging, timing and polarization studies. It will map the gamma-ray sky from 10 MeV to a few GeV with unprecedented spatial resolution. This window on the Universe is unique to detect photons produced directly by relativistic particles, via the decay of neutral pions, or the annihilation or decay light from anti-matter and the putative light dark matter candidates. A wealth of questions can be probed among the most important themes of modern physics and astrophysics. The PANGU instrument is a pair-conversion gamma-ray telescope based on an innovative design of a silicon strip tracker. It is light, compact and accurate. It consists of 100 layers of silicon micro-strip detectors of 80 x 80 cm(2) in area, stacked to height of about 90 cm, and covered by an anticoincidence detectors. PANGU relies on multiple scattering effects for energy measurement, reaching an energy resolution between 30-50% for 10 MeV - 1GeV. The novel tracker will allow the first polarization measurement and provide the best angular resolution ever obtained in the soft gamma ray and GeV band.