Study of the Material within the Run-2 ATLAS Inner Detector

The material in the ATLAS Inner Detector (ID) is studied with several methods, using a sample of \sqrt{s}=13 TeV pp collisions collected in 2015 during Run II of the LHC. The material within the innermost barrel regions of the ID is studied using reconstructed secondary vertices from hadronic interactions and photon conversions. The layout of the cables, cooling p ipes and support structures (services) associated with the Pixel detector, in the region in front of the Silicon Microstrip detector (SCT), was modified in 2014. The material in this region was studied by measuring the efficiency with which tracks reconstructed only in the Pixel detector can be matched to tracks reconstructed in the full ID (track extension efficiency). The results of these studies are presented together with a comparison to previous measurements and a description of their impact on physics analyses and Monte Carlo simulation.