Photodetectors for the CMS hadron calorimeters

Hadronic energy measurements in the central and end cap regions of the Compact Muon Solenoid (CMS) detector will be made using sampling calorimeter techniques with plastic scintillator tiles as the sensitive layers. Plastic fibers doped with wavelength shifting fluors embedded in each tile are used to extract the scintillation light. Clear plastic wave guide fibers carry the shifted light to photodetectors located on the outer surface of the calorimeter structure. Environmental constraints and physics performance requirements for these photodetectors are presented. Candidate photodetector technologies are discussed, and the hybrid photomultiplier tube technology is identified as most promising.