Initial Tests on First Full-size ECAL Endcap Crystals
At the end of last year the first full size ECAL endcap crystals were delivered to CERN.Thirty in number, they were produced to the final geometrical specifications; 220mm long with a rear square face of 30mm and a front square face of 28.6mm. All were delivered polished. The visual inspection , dimension, transmission, light yield and light yield uniformity tests carried out since are discussed , with particular emphasis on the light yield uniformity. The results are very encouraging. suggesting that the endcap crystals will not need uniformisation.
Low dose-rate irradiation set-up for scintillating crystals
Abstract With a 1 Ci 60 Co-source we measured the radiation damage and its recovery in PbWO 4 crystals. The method consists in measuring the anode current produced in the silicon diode of a Hybrid PhotoMultiplier Tube (HPMT) during the irradiation of the crystal. At regular time intervals, we took photon counting spectra with the same HPMT. By checking the resulting channel positions of the photoelectron peaks, we controlled the stability of our experimental set-up. Temperature control and monitoring were achieved by forced thermostatized water circulation inside the irradiation box and by using a PT100 and two AD590 temperature probes. First results on irradiations of a few PbWO 4 crystals are presented and future plans are communicated.
Ignition and burning rates of segregated waste combustion in packed beds.
Recent developments in national recycling and re-use programmes for municipal waste have led to segregation of an increasing proportion of waste to enhance material recovery. Several of the segregated streams contain materials that can not viably be re-used or recycled but can be used for energy recovery. In this study, the combustion of cardboard and waste wood was investigated in a small-scale packed bed reactor in order to provide fundamental data for the design/operation of moving bed furnaces. Key parameters of combustion including the ignition and burning rates were evaluated for various air flowrates and compared to the modelling results. Two successive stages of combustion were identified for both samples: the propagation of ignition front into the bed and combustion of the fuel above the ignition front. The burning rate of cardboard reached a peak of about 300 kg/m(2)h at the air flowrate of 936 kg/m(2)h and decreased at higher air flowrates. For waste wood, both the ignition and burning rates increased in the tested range of the air flowrate up to 702 kg/m(2)h, of which the values were very close to those for the cardboard. The model prediction was in good agreement with the test results for waste wood. However, the burning rate for cardboard was under-predicted due to strongly irregular shapes of the fuel.