Radiation damage in the LHCb VELO

LHCb is a dedicated experiment to study new physics in the decays of beauty and charm hadrons at the Large Hadron Collider (LHC) at CERN. The Vertex Locator (VELO) is a silicon micro-strip detector which surrounds the LHCb interaction point and provides μ m resolution of charged tracks and vertex positions. The tip of the VELO sensors is predicted to receive a dose of 0.5 × 10 13 1-MeV n eq / cm 2 per fb of data. The highest fluence of any silicon tracker at the four major LHC experiments. Radiation damage studies have been carried out during the first two years of data taking at LHCb for all 88 sensors of the VELO. Radiation damage has been observed in all sensors, with those sensors in the highest fluence regions showing evidence of type inversion. Radiation induced charge loss due to the second metal layer on the sensors is also observed.