The LHCb Hadron Calorimeter

The Hadron Calorimeter of LHCb is a sampling iron-scintillator calorimeter of 5.6 δ1 thickness with structure arranged along the collider beam direction. The light readout is performed with WLS fibers running along the scintillator tile edges. The fast front end electronics allows to digitize events at 40 MHz without dead time. The self-calibration system based on 137Cs radioactive source embedded into the calorimeter structure allows to obtain absolute calibration with precision of about 2It is also equipped with a LED monitoring system, which allows to follow the PMT response variations during physics data taking.