Electrical tests and geometrical measurements on wafers and ladders of the GLAST tracker system

The Large Area Telescope of the GLAST mission is a telescope for gamma rays in the range 10 MeV–300 GeV. It consists of a Silicon Strip Detectors’ Tracker and a CsI e.m. calorimeter. The total surface of silicon detectors is almost 80 m2, so it will have the largest equipped area among all space experiments. The Tracker consists of 9219 wafers, 8.9 cm×8.9 cm cross-section and 400 μm thick. The strip pitch is 228 μm and each strip is 64 μm wide. Electrical and geometrical measurements are being performed on both wafers and ladders. The I–V and C–V characterization results on the first 2000 wafers and measurements of the geometric dimensions is presented; the ladders assembly procedures is described and workmanship tests by means of electrical and geometrical measurements is also shown.