The LHCb hadron calorimeter

The Hadron Calorimeter (HCAL) is designed for the LHCb experiment. The main purpose of the detector is to provide data for the L0 hadron trigger. The HCAL is designed as consisting of two symmetric movable parts of about 500 ton in total getting in touch in operation position without non-instrumented zones. The lateral dimensions of an active area are X = 8.4 m width, Y = 6.8 m height, and is distanced from the interaction point at Z=13.33 m. Both halves are assembled from stacked up modules. An internal structure consisting of thin iron plates interspaced with scintillating tiles has been chosen. Attention is paid to optimize the detector according to the requirements of the experiment, reducing the spending needed for its construction. Different construction technologies are being discussed. The calorimeter properties have been extensively studied with a variety of prototype on the accelerator beam. The calibration with a radioactive source and module-0 construction experience is discussed.