Cerium fluoride crystals for calorimetry at LHC

High-resolution homogeneous calorimetry is a fully justified for part of the physics program at LHC. In September 1992, two Letters of Intent sent to the LHC Committee proposed CeF3 crystals for calorimetry. The main design features of calorimeters for LHC are discussed. The severe constraints LHC imposes on detectors make the use of ''classical'' crystals impossible. Therefore, a large R and D effort has been undertaken by the Crystal Clear Collaboration in order to find new, dense, fast and radiation hard crystals. A good candidate, cerium fluoride, has been identified and studied. It is interesting at this stage to review the specifications of scintillators for LHC and to see how well available data on CeF3 luminescence, decay time, light yield, optical transmission and resistance to radiation meet them. Milestones to reach before starting a large scale crystal production in view of the eventual construction of a calorimeter, are also discussed. (orig.)