https://doi.org/10.1051/epjconf/202532000004
Precise time and energy measurement with a homogeneous calorimeter
1 Université Paris-Saclay, France
2 CEA Saclay - IRFU, France
* e-mail: francesco.orlandi@cern.ch
Published online: 7 March 2025
The CMS experiment at LHC has a 15 years experience with the energy measurement of electrons and photons produced in high-luminosity high-energy collisions with a homogeneous electromagnetic calorimeter (ECAL). The PbWO4 crystal calorimeter must operate at a high rate in a harsh radiation environment: changes in detector response need to be corrected for and dedicated techniques are used to mitigate the large number of overlapping interactions (pileup). It also measures the arrival time of the particles with a precision (150 ps). After the upgrade of the readout electronics for the LHC Phase-2, the time resolution will reach 30 ps for energies higher than about 50 GeV. This will be particularly important with the foreseen average pileup level up to 200. A summary of the performance of the CMS ECAL from its development to the ongoing Run 3 is presented, along with the results measured with the upgraded electronics at recent beam tests.
© The Authors, published by EDP Sciences, 2025
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