07 Dec 2021



ATLAS Tracking Upgrade - High-Speed Data Acquisition


Co-supervisors: PPD - B. Smart and M. Wielers, University College London - A. Korn

The Large Hadron Collider (LHC) at CERN will be upgraded to become the High-Luminosity LHC (HL-LHC), providing more proton-proton collisions per second than the current LHC. This will allow for greater precision in physics measurements, and further reach in searches for new physics. For this upgrade, the tracking detector which forms the innermost section of the ATLAS Detector closest to the collisions will be replaced with a new tracking detector, the ITk. The ITk will use Silicon sensors to detect and measure the paths and momenta of high-energy particles. It will comprise an inner section of Silicon pixel sensors, and an outer section of Silicon strip sensors. Custom high-speed radiation-hard electronics are being developed to read out these sensors. At the Rutherford Appleton Laboratory (RAL), 1500 pixel sensor modules, comprising 6000 front-end chips, must be pre-tested and qualified, mounted to carbon fibre support structures with high precision, wired into data readout, control, and powering circuitry, before the completed structures are tested for combined operation. A full ITk data readout chain will be used for these tests. Due to the large number of chips and modules to be tested, considerable automation will be required.

As part of the ATLAS collaboration, a student will join RAL and University College London (UCL), to jointly develop ITk pixel data-readout and test infrastructure, building on the considerable ITk and data readout expertise and leadership at these institutes. The student will help to build and develop full pixel readout chains, and will identify and develop methods for quantifying and comparing pixel module performance, and with that rapid automated sensor qualification. The student will also develop and perform first operation, testing, and qualification of combined pixel structures at RAL. The student will gain and use skills in computer programming, electronics, FPGA firmware development, high-speed digital communication, and international collaboration on a large-scale scientific project.

There will also be an opportunity to pursue physics analysis with the ATLAS Detector utilising the existing ATLAS tracking detector: Unconventional signatures of current great interest are long lived particles (LLPs), which decay in the detector itself. These LLPs have been predicted by a number of New Physics models, including dark matter candidates. For this task a dedicated track reconstruction algorithm was developed to find tracks starting in the tracking volume. A current analysis using this is the search for exotic decays of the Higgs boson into long-lived particles decaying into b-quarks and tau leptons. An ultimate goal will be placing more model independent limits on the cross-sections of highly displaced vertices and hence LLP production. The student will join an existing team already involved in this analysis, allowing a greater focus of person-power on this topic, increased progress, and better support. The applicant will have the option to be based at CERN for a period of time, and will present their work at international conferences.

The student will be supervised by Dr Ben Smart, Dr Monika Wielers, and Dr Andreas Korn. Daily local supervision will be supplemented by regular video and in person team meetings. Existing students and postdocs will lend further support.

Interested in this project:

Due to the funding structure of this joint studentship please also apply already at this point not only to RAL but also directly to UCL https://www.hep.ucl.ac.uk/postgrad/

For more information please contact Ben Smart.

Contact: Smart, Ben (STFC,RAL,PPD)