Search for dark matter and novel tracking detector technologies for the upgraded ATLAS tracker

Domain topic

Particle Physics



Dark matter is one of the biggest mysteries of our universe. At the Large Hadron Collider (LHC), dark matter particles could be produced by colliding protons. Since dark matter processes are very rare, the proton-proton collision rate at the LHC needs to be very high to ensure that we are able to produce those elusive particles. To cope with this, the ATLAS experiment is designing and building new tracking systems to reconstruct the trajectories of the charged particles from the collisions. The high-granularity, radiation-hard ATLAS Inner Tracker (ITk) will substitute the current tracking system after the next upgrade of the LHC. Upcoming particle physics data analyses concerning dark matter particles will heavily rely on these novel tracking systems. Having a precise tracking system and fast decisions based on tracking information are both essential points to distinguish dark matter signals and background from known particles.

The upgrade of the LHC planned for 2026 will bring new insights on the fundamental constituents of matter, and on the nature of dark matter. It will yield the largest-ever dataset of proton-proton collisions, about 10 times larger than what will be available from the LHC operation before. For every single “collision event” recorded by the detectors, there will be up to 200 simultaneous proton-proton collisions per second as opposed to the current 60, and a new tracking system, the ITk, needs to be built to distinguish signal from backgrounds.

Project Description

One of the core elements of the ITk are the so-called strip tracker modules, consisting of a silicon sensor and its associated read-out, power and control electronics. The modules are being manufactured and tested at DESY and Lund University. They need to undergo an extensive quality control (QC) and quality assurance (QA) program to be assessed as “detector ready”. The QA/QC procedures include optical metrology, high- speed electrical measurements, thermal cycling, and mechanical evaluation. Establishing the procedures and test setups at both laboratories and performing the measurements are a core part of this project and fundamental for the functioning of the ITk and its use in physics analysis. Since the LHC will not take data with the ITk until after the end of this graduate school, the project involves the analysis of current data searching for dark matter particles using, among others, real-time techniques in synergy with the first PhD student, as well as a study of the prospects for improvement after the LHC upgrade.

Methodological keywords

Optical systems, detectors, assembly and calibration, control and synchronisation, simulation start-to-end