Radiation Damage Simulation for the ATLAS Inner Tracker (ITk) System*

ATLAS is one of four major experiments at the Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN). In its current run 3 (which began in July 2022), protons collide at a record center-of-mass energy of 13.6 TeV, with over a billion particle collisions occurring each second.

The High Luminosity upgrade to the LHC (HL-LHC) is expected to be operational in 2029. It is expected to produce significantly more collisions than the current LHC and produce, for example, at least 15 million Higgs bosons per year, compared to around three million from the LHC in 2017.

The inner tracker system (ITk) of the detector receives the most radiation damage from these collisions. This damage impacts both the physics performance and the operating conditions. Monte Carlo (MC) simulations help model this damage to the detector. In the current run, the simulations reproduce and anticipate effects with a precision of 1%. Just as the physical ATLAS experiment is being upgraded, the MC simulations must also be updated to incorporate the expected modifications. This presentation will describe studies on the simulation of radiation damage to the ITk for the upgraded detector.