ATLAS Tile Calorimeter system collaboration (238 authors)Santos, S.P.Amor DosAraque, J.P.Castro, A.BlancoCarvalho, J.Castro, N.F.De Sousa, M.J.Da Cunha SargedasFiolhais, M.C.N.Galhardo, B.Gomes, A.Jorge, P.M.Martins, P.J.MagalhaesMaio, A.Maneira, J.Seabra, L.F.OleiroOnofre, A.Pedro, R.Pina, J.Santos, H.Saraiva, J.G.Silva, J.Delgado, A.TavaresVeloso, F.2019-02-042019-02-042016-10-12http://dx.doi.org/10.1088/1748-0221/11/10/T10005http://hdl.handle.net/10400.26/27161This article describes the Laser calibration system of the Atlas hadronic Tile Calorimeter that has been used during the run 1 of the LHC. First, the stability of the system associated readout electronics is studied. It is found to be stable with variations smaller than 0.6 %. Then, the method developed to compute the calibration constants, to correct for the variations of the gain of the calorimeter photomultipliers, is described. These constants were determined with a statistical uncertainty of 0.3 % and a systematic uncertainty of 0.2 % for the central part of the calorimeter and 0.5 % for the end-caps. Finally, the detection and correction of timing mis-configuration of the Tile Calorimeter using the Laser system are also presented.engjournal article2019-02-04