ROC chips for imaging calorimetry at the International Linear Collider

Imaging calorimetry at the International Linear Collider requires new detectors with one hundred million channels that will be read-out with calorimetric performance, that is percent accuracy over 16-bit dynamic range. The readout electronics must be highly integrated and ultra-low power (mW per channel) to be embedded inside the detectors. To tackle these challenges, R&D started in 2000 under the CALICE collaboration framework and FP6 EUDET, FP7 AIDA EU programs. Several detector technologies have been proposed and tested: Tungsten/Silicon for the Electromagnetic Calorimeter (ECAL), scintillating tiles readout by Silicon PhotoMultipliers (SiPM) for an Analog Hadronic Calorimeter (AHCAL) and RPC/Micromegas/GEM for a Semi Digital Hadronic Calorimeter (SDHCAL). Detector prototypes have been built and readout by ReadOut Chips (ROC chips) named SKIROC, SPIROC and HARDROC and designed in SiGe 350 nm technology by the IN2P3 OMEGA group. Different front-end architectures have been integrated for the various sensors and, to optimize the commonalities between the various detector proposals, the chips share a common backend and readout scheme. In order to address the numerous challenges, three generations of chips have been foreseen. The first generation consisted in analog readout ASICs that allowed characterizing the detector concepts in testbeam, referred to as CALICE physics prototypes. The second generation addresses the integration issues with embedded electronics and performs analog amplification, shaping, internal triggering, digitization and local storage of the data in memory. Thousands were produced in 2010 to equip CALICE technological prototypes and are being tested by IN2P3, DESY, CERN, and KEK groups. Zero suppression will be added in the 3rd generation chips, which is a major modification as it increases the complexity of the digital part. The performance of these chips on testbench and at the system level will be detailed in this presentation.