The CASTOR calorimeter in the CMS experiment - detector design and data acquisition

The Castor calorimeter will be installed in the very forward region (5.1 < η< 6.6) of the CMS experiment at the LHC. It is a Cherenkov sampling calorimeter, which can tolerate the radiation hard environment in the forward region and consists of an electromagnetic and a hadronic section, with successive layers of tungsten plates as absorber and fused silica quartz plates as active material. The Cherenkov light produced by the incoming charged particles is collected in reading units along the depth of the calorimeter and transported onto PMTs by air-core light-guides. The physics topics, which will be addressed with the CASTOR calorimeter will be discussed. These measurements impose certain requirements on the detector design and the data acquisition system. The layout of the data acquisition system will be described and the results of first tests will be shown