Lessons learned from the Dط Silicon Microstrip Tracker

A Silicon Microstrip Tracker has been built and installed into the upgraded DØ detector for Run II at the Tevatron. It provides excellent b-hadron identification capability by precise tracking despite some operational problems. Our irradiation study indicates the lifetime of the first layer to be 3.6– 4.9 fb - 1 or (11–15) × 10 12 / cm 2 1 MeV neutron equivalent. An addition of an innermost layer to the existing detector is planned which will insure the functionality through the Run II.