PT Journal AU ATLAS Collaboration (Aad, Gea Aparisi Pozo, JA Bailey, AJ Cabrera Urban, S Castillo, FL Castillo Gimenez, V Costa, MJ Escobar, C Estrada Pastor, O Ferrer, A Fiorini, L Fullana Torregrosa, E Fuster, J Garcia, C Garcia Navarro, JE Gonzalez de la Hoz, S Gonzalvo Rodriguez, GR Guerrero Rojas, JGR Higon-Rodriguez, E Lacasta, C Lozano Bahilo, JJ Madaffari, D Mamuzic, J Marti-Garcia, S Martinez Agullo, P Mitsou, VA Moreno Llacer, M Navarro-Gonzalez, J Poveda, J Prades IbaƱez, A Rodriguez Bosca, S Ruiz-Martinez, A Salt, J Santra, A Sayago Galvan, I Soldevila, U Sanchez, J Torro Pastor, E Valero, A Valls Ferrer, JA Vos, M TI Alignment of the ATLAS Inner Detector in Run 2 SO European Physical Journal C JI Eur. Phys. J. C PY 2020 BP 1194 EP 41pp VL 80 IS 12 DI 10.1140/epjc/s10052-020-08700-6 LA English AB The performance of the ATLAS Inner Detector alignment has been studied using pp collision data at v s = 13 TeV collected by the ATLAS experiment during Run 2 (2015-2018) of the Large Hadron Collider (LHC). The goal of the detector alignment is to determine the detector geometry as accurately as possible and correct for time-dependent movements. The Inner Detector alignment is based on the minimization of track-hit residuals in a sequence of hierarchical levels, from global mechanical assembly structures to local sensors. Subsequent levels have increasing numbers of degrees of freedom; in total there are almost 750,000. The alignment determines detector geometry on both short and long timescales, where short timescales describe movementswithin anLHCfill. The performance and possible track parameter biases originating from systematic detector deformations are evaluated. Momentum biases are studied using resonances decaying to muons or to electrons. The residual sagitta bias and momentum scale bias after alignment are reduced to less than similar to 0.1 TeV-1 and 0.9 x 10(-3), respectively. Impact parameter biases are also evaluated using tracks within jets. ER