A scalable data acquisition system for the CALICE tile hadron calorimeter

The data acquisition system for a highly granular Analogue Hadron Calorimeter (AHCAL) for the future International Linear Collider (ILC) will be presented. The developed DAQ chain has several stages of aggregation and scales up to 4 million channels in the main barrel foreseen for the AHCAL design. The front-end electronics will be embedded in the detector layers in between absorber plates without active cooling. The ILC has a specific timing of less than 1 ms of a spill with 2820 bunches followed by 199 ms of idle time used for slow readout, which allows the detector to be operated in power-pulsing mode in order to meet the power dissipation budget. This timing is reflected in the architecture of the DAQ from the very front-end ASIC embedded in the detector layers between absorber plates to the largest aggregation device, the Link Data Aggregator, which has 96 HDMI connectors matching the AHCAL steel absorber plate spacing, four Kintex7 FPGAs and a central Zynq System-On-Chip. The DAQ meets the ILC timing and bandwidth, which will be shown. The same DAQ is used also for AHCAL prototype beam tests, which require rather continuous data taking. The DAQ architecture, data flow, timing and performance will be presented in detail. The performance has been demonstrated in recent beam tests at the CERN SPS in 2015 and at DESY in 2016.