Development of high-performance timing detectors for the CMS forward proton spectrometer


  • Call:

    PT-CERN Call 2021/2

  • Academic Year:


  • Domain:


  • Supervisor:

    Michele Gallinaro

  • Co-Supervisor:

    Joao Varela

  • Institution:

    Instituto Superior Técnico (Universidade de Lisboa)

  • Host Institution:

    Laboratório de Instrumentação e Física Experimental de Partículas

  • Abstract:

    A high Precision Proton Spectrometer (PPS) has been taking data as a subsystem of the CMS experiment [1]. It uses a timing detector (either diamond or silicon-based) in order to measure the time of flight (ToF) of the two forward protons produced in the interaction point in the CMS detector. One of the major challenges of operating such detectors at the HL-LHC is the "pileup", or additional collisions occurring in the same proton bunch crossing as the collision of interest. By precisely measuring their ToF, forward protons produced in these collisions can be correctly associated to the correct collision vertex, enabling rare photon-photon interactions to be reconstructed at the maximum pileup foreseen for the HL-LHC. In order to fully resolve all collisions, timing precisions of ~20ps or less will be required. In particular it would greatly improve the rejection of backgrounds in searching for high mass resonances, such as a resonant Higgs pair production [2,3,4]. During Run2 of the LHC, fast timing detectors were operated and achievedresolutions of ~100ps with high efficiency. For the HL-LHC, new technologies will be required to cope with the pileup, radiation, and event rates, both in terms of sensors and readout electronics [5]. The subject of this thesis focuses on the preparation of the detector technology to address the challenges at the HL-LHC by exploring the latest developments in timing detectors and electronics, under extreme radiation. Physics studies aimed at determining the sensitivity to New Physics processes will also be pursued. The research will be carried out in the context of the Portuguese participation in the CMS experiment at the LHC, in the framework of the activities of one of the outstanding research groups in High-Energy Physics in Portugal. Citing the Report of the recent Institutional Evaluation performed by an international review panel nominated by FCT: “The LIP-CMS group, while small in size, is really outstanding and world-class”.