A new Scintillating Fibre (SciFi) Tracker has been installed as part of the last LHCb Upgrade (2019-2022) to increase the tracking efficiency and to implement a trigger-less 40 MHz electronic readout system. The tracker is made of staggered scintillating fibres and read out by Silicon Photomultipliers (SiPMs).
At the end of the Run 3 data taking period in 2025, an integrated luminosity of L = 40 fb-1 will be reached, which is close to the SciFi Trackers’ design luminosity of L = 50 fb-1.
Thus the fibre modules most affected by the radiation will be replaced during the next long shutdown (2026 - 2029). This also allows to install microlens-enhanced SiPMs to mitigate the radiation-induced ageing effects by improving the Photon Detection Efficiency (PDE).
A further LHCb detector upgrade is planned for Run 5 (2035 - 2038) to run at a higher instantaneous luminosity and accumulate 240 fb-1. This will result in an increased occupancy of the tracker and a ten times higher radiation environment. A hybrid tracker will replace the SciFi Tracker, combining a silicon pixel detector, employed in the inner region to cope with the high occupancy, with a SciFi system covering the outer region. One of the main challenges for this SciFi will be the large increase in SiPM dark noise
caused by the high irradiation.
This talk will give an overview of the challenges for the future upgrades of the SciFi technology, with a focus on the latest results of the photodetector R&D performed at EPFL.
Stefan Meyer Institute