First results from the LHCb Vertex Locator

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 the silicon detector surrounding the interaction point and will be located only 7 mm from the LHC beam during normal operation. The beauty and charm hadrons are identified through their flight distance in the VELO, and hence the detector is critical for both the trigger and offline physics analyses. The VELO has been commissioned and successfully operated during the initial running period of the LHC. The detector has been time aligned to the LHC beam, and spatially aligned. Preliminary operational results show a signal to noise ratio of 20:1, a cluster finding efficiency of 99.6%, and a best single hit precision of 4 μ m .