  With the successful construction and operation of a highly granular hadron
calorimeter system, featuring approx. 22000 individually read out SiPM-on-tile
channels, the CALICE collaboration has set the next milestone in proving the
scalability of the concept for a future high energy linear collider experiment.
For this large sample of photosensors a new approach of quality control was
required to sufficiently characterise and monitor device parameters for both,
test bench and in-situ beam test data. In the presence of temperature
fluctuations during operation, it was possible to stabilise the SiPM responses
with a fully automated adjustment of the bias voltage based on frequent
temperature measurements, thanks to the excellent parameter uniformity of the
devices. This contribution presents the results of SiPM parameter studies
during the construction and commissioning phase and reports about the system
performance and the experience of automated temperature compensation at system
level during operation.
