Radiation effects in the LHC experiments: Impact on detector performance and operation

This report documents the knowledge and experiences gained by the LHC experiments in running detector systems in radiation environments during 2010–2018, with a focus on the inner detector systems. During this time, the LHC machine has delivered a large fraction of the design luminosity to the experiments and the deleterious effects of radiation on detector operation are being observed and measured. It is timely to review the findings from across the experiments. Questions we aim to answer include: Are the detector systems operating and performing as expected? How reliable are the radiation damage models and predictions? How accurate are the Monte Carlo simulation codes? Have there been unexpected effects? What mitigation strategies have been developed? A major goal of this report is to provide a reference for future upgrades and for future collider studies, summarizing the experiences and challenges in designing complex detector systems for operation in harsh radiation environments.