Crystal Clear Collaboration

The Crystal Clear collaboration (RD-18) was set up in 1990. The aim was to study the possible use of heavy scintillating materials in experiments at LHC. This project was quite successful and the CMS experiment is now building a large electromagnetic calorimeter using PbWO4 scintillating crystals. In 1997, the collaboration decided to turn its attention to the development of scintillating materials and instrumentation for nuclear medicine. The new technology will be based on the use of new scintillating materials and new photo detectors, which together allow the development of much better detector elements. Regarding the new scintillators, we are concentrating our attention on LuAP:Ce. This material has many very promising properties. It is very fast, with a decay time of only 18ns, has a large light yield and a good energy resolution. But we are also looking into the possibility to improve the light yield of PWO. This last scintillator has many excellent properties as for its use in PET, except for its low light yield. But we believe it is possible to improve considerably this light yield if one can relax on other requirements such as radiation hardness. For the photo-detector we believe that the progress in avalanche photo-detectors has now reached the point where APD's offer better performance at comparable cost than photo-multiplier tubes.
We will design and build several small animal PET scanners, making use of a new technology outlined above. There is a growing interest for such devices for drug development. We have organised around our collaboration a number of local centres. Each local centre establishes contacts with the local medical community and obtains the funding to participate in the Crystal Clear project and build a high resolution small animal PET scanner for its associated medical centre. The development of the new technology and the design and construction of the new machines are done in close collaboration between the different centres and the other members of Crystal Clear. These PET scanners will be ready and fully operational in 2003.
At present local centres are set-up and funded in France, Belgium and Germany. In a number of other countries (for instance Switzerland and Portugal) attempts are also under way to create similar local centres.