Speaker
Description
The LHCb experiment is going to face much higher occupancies and radiation levels in its high-luminosity phase, requiring major upgrades of the electromagnetic calorimeter (ECAL). As a first step, an enhancement is planned during Long Shutdown 3 (LS3) of the LHC to mitigate ageing in the central region and to ensure stable performance after Run 3. This upgrade introduces Spaghetti Calorimeter (SpaCal) technology into the innermost part of the ECAL. A total of 176 new SpaCal modules with radiation-tolerant scintillating plastic fibres will be installed: the 32 closest to the beam line will use 3D-printed tungsten absorbers, while the remaining 144 will employ lead absorbers produced with a novel casting approach. Both designs have been studied extensively in test-beam campaigns at DESY and CERN, where the measured performance matches simulations and meets the requirements for operation at higher luminosities. The scintillating fibres will be coupled via radiation-hard light guides to fast photon detectors, with new front-end electronics for 3072 additional readout channels. Modifications to the ECAL support platform are also foreseen to accommodate the installation. In addition, the existing Shashlik modules will be rearranged to better follow the occupancy map, improving uniformity at high luminosity. The LS3 intervention will not only restore ECAL performance for Run 4, but also anticipate several features of the PicoCal upgrade foreseen for LS4.
