Luminosity Measurement Using Cherenkov Integrating Detector (LUCID) in ATLAS

LUCID (LUminosity measurement using Cherenkov Integrating Detector) is a Cherenkov counter designed to monitor the luminosity in the ATLAS experiment. Since the final accuracy of the measurement of some crucial physical quantities in the LHC program will depend on the precision of the luminosity measurement, it is mandatory to push the latter to its best. This in turn implies the need to monitor the beam conditions. In this paper an overview of LUCID is given. After a description of the detector, an insight into the luminosity measurement strategy in ATLAS is given, as well as a description of the calibration strategy of LUCID.