The ATLAS Tile Calorimeter performance and its upgrade towards the High-Luminosity LHC

The Tile Calorimeter is a hadronic calorimeter covering the central region of the ATLAS experiment. The signals are read-out by wavelength shifting fibres coupled to the photomultiplier tubes. The front-end electronics process those signals from which the energies are inferred. Each stage of the inference is calibrated using the calibration systems of the Tile Calorimeter. The performance of the calorimeter has been measured and monitored using calibration data, cosmic ray muons and the collision data acquired during LHC Run 1 and Run 2. The High-Luminosity phase of LHC (HL-LHC), is expected to begin in 2028. The electronics of the calorimeter will be replaced to cope with the higher trigger rate, radiation level and pile-up conditions. Prototypes of this new electronics were tested within a demonstrator module both in test beam and calibration runs. The performance and calibration of the Tile Calorimeter are summarized, as well as the results obtained from the test of the new electronics prototypes.