Author/Authors :
Auffray، نويسنده , , E. and Bouquerel، نويسنده , , E. and Chevenier، نويسنده , , G. and Lecoq، نويسنده , , P. and Pérez-Prado، نويسنده , , L. and Sempere-Roldan، نويسنده , , P. and Schneegans، نويسنده , , M. and Cavallari، نويسنده , , F. and Costantini، نويسنده , , S. and Dafinei، نويسنده , , I. and Diemoz، نويسنده , , M. and Longo، نويسنده , , E. and Meridiani، نويسنده , , P. and Organtini، نويسنده , , G. and Paramatti، نويسنده ,
Abstract :
The barrel part of the CMS electromagnetic calorimeter consists of about 75 000 Lead Tungstate (PbWO4) crystals arranged in 36×4 modules which are assembled in two Regional Centres, in Rome and at CERN. Two automatic machines have been designed to check the crystal quality before assembly. The main crystal characteristics are compared to a set of specifications included in the contract with the crystal producers. The measurement stability and cross-calibration between the two machines is a fundamental issue, which has to be monitored throughout the construction phase. This paper describes comparisons between measurements made at the two regional centres to ensure a consistent and reliable crystal quality control.
Keywords :
Calibration , Electromagnetic calorimeter , Scintillating crystals , Optical properties , measurement automation
