Status of PWO crystal production for the electromagnetic calorimeter of CMS and of its construction

The CMS Electromagnetic Calorimeter will be composed of nearly 80,000 lead tungstate crystals. Owing to the high-energy resolution aimed at it and to the hostile Large Hadron Collider (LHC) radiation environment, a rigorous quality control of the crystals is performed on several parameters such as light yield, uniformity of the light collection or radiation hardness. The results of this quality control for the first 15,000 crystals delivered and characterized at the CERN Regional Centre by Bogoroditsk Techno-Chemical Plant are presented here. In addition, an overview of the construction status is given.