Operation and radiation damage studies of the ATLAS pixel detector

The ATLAS pixel detector provides the innermost layers of the InnerDetector tracker. Due to its proximity to the collision region the pixel detector hasbeen exposed to considerable levels of radiation during its operation at the LHC,up to $2-10^{14}n_{eq}/cm^2$. By the end of Run 3, in 2023, the integrated luminosity andfluence will have increased further by an order of magnitude. The radiation damageeffects are already noticeable and will increasingly affect the detector performancein the coming years. Monte Carlo simulation are becoming necessary to model thechange in detector response