Luminescence and scintillation in cerium-activated oxide crystals with complex structure are quenched by cc-doping with ytterbium. It was determined that Ce3+ luminescence is quenched by tunneling ionization and scintillations are suppressed in addition by the destruction of relaxing excited host matrix states by Yb3+ ions and nonradiative transitions Ce3+ 4 (Yb3+)-.
The results from experimental and certification measurements of the optical transmission and technical light yield of a technological lot of PWO crystals intended for the central part of the CMS electromagnetic calorimeter at CERN are analyzed. Statistical estimates of the crystals' radiation hardness are obtained, allowing the calorimeter energy resolution to be evaluated under operating irradiation conditions.
A compact high power microwave (HPM) source is reported. It generates short pulses by direct excitation of an antenna with a 300 kV Marx generator. Oil insulation is used to protect capacitor banks from breakdown, while discharge gaps are designed to work in air. The Marx generator risetime is less than 50 ns. The disk-cone antenna is also oilinsulated and operates in the self-breakdown regime. Radiated pulse has the duration about 2 ns and the spectrum from 800 MHz to 2 GHz. The HPM source is used for studying the vulnerability of computers and different electronic components.
The influence of the irradiation of PWO crystals on the characteristic timing parameters of changes in their optical transparency and subsequent recovery during the working cycle of the LHC accelerator (CERN) was studied. PWO crystals were irradiated with a working dose corresponding to the radiation load in the electromagnetic calorimeter. A method for evaluating the influence of the change in the optical transparency of scintillation crystals on the statistical term in the energy resolution of the electromagnetic calorimeter in intense radiation fields is proposed. This method is applied to the development of the technology of mass production of radiation-hard scintillation crystals used in electromagnetic calorimetry and to its certification.
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