A few technologically-advanced prototypes of 1x1 m2 were constructed. Optimised for Particle-Flow hadron calorimetry at a LC, they are segmented into pads of 1x1 cm2, each read out by simple threshold electronics. Their standalone performance were studied in great details in testbeams. In addition, expected performance of a Micromegas calorimeter were deduced from the measured three-dimensional shape of high-energy pion showers inside the CALICE semi-digital hadron calorimeter (SDHCAL).
Absorption in the gas of highly ionising particles produced in hadron showers occasionally triggers a discharge. This can be a serious show-stopper for high-rate applications such as forward calorimetry at a high-luminosity LHC experiment. Discharge protections based on resistive films were successfully implemented on small-size prototypes. Several resistive configurations were actually studied to minimise the time necessary for charge evacuation and the resulting efficiency and linearity losses.