RESISTANCE OF LEAD TUNGSTATE AND CERIUM FLUORIDE TO LOW RATE GAMMA IRRADIATION OR FAST NEUTRONS EXPOSURE
We present here the results of recent low dose rate gamma irradiation of lead tungstate and cerium fluoride long crystals, and, for lead tungstate only, fast neutron exposure. For the low rate tests, recovery processes are taking place during irradiation and, compared to the usual high rate tests, only a very low damage is noticed, if any. No saturation effect is observed in these previously irradiated samples. For the neutron tests, a very small variation with fluence is not excluded, after a fast saturation at low fluence. The samples tested here are very resistant.
CMS Paper September 01 , 2009 Radiation hardness qualification of PbWO 4 scintillation crystals for the CMS Electromagnetic Calorimeter The CMS Electromagnetic Calorimeter Group
Ensuring the radiation hardness of PbWO4 crystals was one of the main priorities during the construction of the electromagnetic calorimeter of the CMS experiment at CERN. The production on an industrial scale of radiation hard crystals and their certification over a period of several years represented a difficult challenge both for CMS and for the crystal suppliers. The present article reviews the related scientific and technological problems encountered.
The Scintillation Mechanism in PbWO 4 Crystals
It has been shown recently that scintillators based on PbWO{sub 4} (PWO) single crystals are promising candidate for electromagnetic calorimetry in LHC. The origin of blue, green and red luminescence in PbWO{sub 4} crystals has been globally determined. The scintillation mechanism based on sensitization of WO{sub 4}{sup 2{minus}}, (WO{sub 3} + F) centers luminescence by Pb{sup 2+} ions has been found for PbWO{sub 4} scintillators.