The CALICE AHCAL: a highly granular SiPM-on-tile hadron calorimeter prototype

The Analogue Hadron Calorimeter (AHCal) of the CALICE collaboration is a technological prototype for future linear collider detectors, addressing scalability, integration and engineering challenges imposed by the experimental environment. It is based on the SiPM-on-tile technology, where the active layers of the calorimeter are formed by 3 × 3 cm$^{2}$ plastic scintillator tiles placed on top of SiPMs mounted on readout boards that also house SPIROC-2E front-end ASICs. A large prototype with 22 000 channels has been constructed using techniques suitable for mass production and automatic assembly. The calorimeter successfully took muon, electron and pion data at the CERN-SPS. Smaller setups for dedicated measurements were also tested later at the DESY-II facility. Main features of the alternative KlauS ASIC and megatile scintillator designs are also presented.