Modeling of radiation damage effects and digitization for 3D silicon pixel ATLAS detectors

Silicon Pixel detectors are at the core of the current and planned upgrade of the ATLAS experiment at LHC. They constitute the part of ATLAS closest to the interaction point and for this reason they will be exposed – over their lifetime – to a significant amount of radiation: prior to the HL-LHC, the innermost layers will receive a fluence of 10$^{15}$ n$_{eq}$∕cm$^2$ and their HL-LHC upgrades will have to cope with an order of magnitude higher fluence integrated over their lifetimes. The paper presents a new digitization model that includes radiation damage effects for 3D Pixel sensors of the ATLAS Detector. The results of the calculation model concerning charge collection efficiency show a very good agreement with existing data in literature.