The Agile Silicon Tracker:. Construction and Calibration Results

The AGILE (Light Imager for Gamma-ray Astrophysics) gamma-ray satellite will be launched on an equatorial orbit in 2006 to become the only observatory (till the GLAST launch) for gamma rays in the energy range 30 MeV-50 GeV. The scientific payload consists of a silicon tungsten tracker, a CsI(Tl) minicalorimeter, a plastic scintillator anticoincidence system and a coded mask X-ray detector (in the range 15-45 keV). The silicon tracker is the heart of the satellite. It consists of 12 x-y planes of 16 silicon strip detectors per plane for a total of ≈37k channels, organized in 13 Al honeycomb-carbon fiber trays. The first 10 trays have a 245 μm tungsten layer (0.07 X₀) for the photons to convert in a e⁺/e^- pair. The strips are read by analog-digital, low noise, low power and self triggering ASICs, the TAA1s. We will describe the present status of the silicon tracker, whose commissioning has required the equivalent of 10 man-years of tests.