Radiation Damage Effects and Operation of the LHCb Vertex Locator

Vertex Locator (VELO) is a silicon micro-strip detector situated around the interaction point in the LHCb spectrometer at the LHC. The LHCb experiment is dedicated to studying CP violation in the heavy flavor sector and rare decays of B mesons. The precise reconstruction of both the primary and sec-ondary vertices, obtained by the VELO, is crucial in the selection of signal events containing b and c quarks and lifetime measure-ments. VELO consists of two retractable parts that operate at 8 mm from the interaction region. Its proximity to proton beams makes the LHCb VELO a place for studying radiation damage ef-fects in silicon detectors in proton-proton and heavy ion collisions. The latest results from radiation damage studies and their impact on the operation of the LHCb VELO after the first data taking period (Run I) and ongoing Run II are presented in this paper. The main macroscopic parameters, influenced by particle fluence, are described along with selected methods of their monitoring. All the results show that VELO sustains the impact of high fluence of ra-diation, and its performance will not change significantly until the end of Run II.