The silicon tracker (link opens in a new window) is at the heart of the CMS detector. It makes precise measurements of the paths of charged particles as they pass through the CMS magnetic field, allowing the main event vertex, and secondary vertices from decays of heavy quarks, to be reconstructed very precisely. The PPD group worked closely with RAL electronics engineers to design readout electronics for the tracker detector, has been closely involved in beam tests of the detector, and continues to make a substantial contribution to the development of reconstruction and simulation software.
The 4 layers of the tracker inner barrel
CMS HL-LHC upgrade
After Run 3 and during Long Shutdown 3 (LS3), the accelerator will be upgraded to allow ATLAS and CMS to collect integrated luminosities of the order of 300 fb−1 per year and up to 3000 fb−1 during the HL-LHC projected lifetime of ten years. The entire silicon tracking system, presently consisting of pixel and strip detectors, will be replaced. The new tracker will feature increased forward acceptance, increased radiation hard-ness, higher granularity, and compatibility with higher data rates and a longer trigger latency. In addition, the tracker will provide tracking information (on tracks above a configurable transverse momentum threshold) to the L1 trigger, information presently only available at the HLT. This will allow the trigger rates to be kept at a sustainable level without sacrificing physics potential.
At RAL we are working on the tracking of events collected during HL-LHC collisions. Tracking will be performed online and used to better identify events of interest for selection via the L1 trigger.
Above is a RAL CMS PhD student opto-testing a tracker DTC (Data, Trigger and Control) Serenity board. These boards are an essential part of the hardware that will be used for online track reconstruction.