Scintillators and Detectors Generic Activities

Since its creation Crystal Clear is involved in the fundamental study of inorganic scintillators like :

- Understanding scintillating and radiation mechanisms in crystals

After successful installation for the ALICE and CMS experiments at LHC, Crystal Clear has carried on investigations on new scintillators and more particularly on the understanding of scintillation mechanisms and light transfer properties. We have developed, in collaboration with the French company "Le Verre Fluoré", a new family of heavy scintillating fluoride glasses, thus offering excellent perspectives for a new generation of "affordable" calorimeters and Cerenkov detectors. We have also worked in collaboration with the Czech company CRYTUR on the development of high quality Yttrium Aluminate Perovskite (YAP) crystals. We have identified and pioneered LuAP (LuAlO3:Ce) as a very promising new scintillator with a decay time of only 18 ns and a light yield that could possibly be 50% of NaI(Tl).

To summarise, we have established a good understanding of:

• Cerium ion as activator
• Cerium fluoride (CeF₃) as a dense, fast, high light yield and radiation hard scintillator. Through extensive studies of this scintillator, we concluded it was suitable for high energy physics experiments. We worked with industry (Optovac (USA), SIC and BGRI(China), Crytur (Czech Republic)) to develop its production at an industrial scale. At the same time these studies have greatly contributed to our understanding of Cerium emission based scintillators.
• The development of LuAP, LuYAP crystals for medical imaging applications (CERN patent).
• The investigation of Ytterbium based scintillators for solar neutrinos spectroscopy and more recently on LuAG crystals.
• Extensive studies of PWO scintillating properties: we have reached a thorough understanding of the different mechanisms underlying the scintillation and radiation damage processes in PWO crystals and helped the producers in Russia and China to develop mass production at an unprecedented scale and quality level, which was required by the LHC working constraints.
• Heavy fluoride glass scintillators.
• LSO, LYSO.

- Light propagation in crystal

• Simulation work using the Litrani program
• Development and optimization of surface treatment (depolishing, photonic crystals)

- Radiation damage

• PWO
• CeF₃
• Optical glass

- Study of mechanical properties

• Optimization of cutting and polishing
• Characterisation and identification of mechanical constraint