High precision timing measurement in the CALICE analogue hadronic calorimeter

The CALICE Collaboration [1] is developing highly granular calorimeters for a future $e^+ e^-$ linear collider. The development of the calorimeters is driven by the Particle Flow approach (PFA) in order to achieve a jet energy resolution of 3-4% [2]. The Analog Hadronic Calorimeter (AHCAL) is one of the detector concepts based on 30×30×3 mm$^3$ scintillating tiles read out by Silicon Photomultipliers (SiPM) and processed by an ASIC (SPIROC2b) capable to measure the amplitude and the time of individual calorimeter hits. A second generation engineering prototype of the AHCAL is developed to focus on the full scalability of the detector. This prototype is composed of 14 active layers corresponding to 3744 channels inserted into an absorber structure of $4 \lambda_i$ depth. Alternative designs for the scintillating tiles with and without wavelength-shifting fibres and tiles individually wrapped with a reflector foil were used as well as different types of SiPMs. It was tested at the CERN Super Proton Synchrotron (SPS) in summer 2015 with steel and tungsten absorbers, in muon, electron and hadron beams. First results of the AHCAL prototype concerning timing capabilities are shown including timing calibration procedure and comparison to simulation.