SKIROC : A front-end chip to read out the imaging silicon-tungsten calorimeter for ILC

That paper describes the new front-end ASIC "SKIROC" designed to read-out the technologic prototype of Si-W calorimeter for ILC (International Linear Collider). The very high granularity of that new calorimeter designed for particle flow physics involves an unprecedented level of integration. Achieving the read-out of the 82 millions channel of the future calorimeter will be possible by using full integrated system on chip (SoC), as close as possible from the silicon detector. The SoC shall feature self trigger capability to ensure a early zero suppress and therefore avoid a huge data flow to the data acquisition. SKIROC also features a power pulsing supply to fit the beam structure of ILC and save power to improve compactness on the calorimeter by avoiding active cooling. A gain of two orders of magnitude is saved on the power consumption by using idle mode on the front-end electronics. The analogue data are converted into digital inside the ASIC and are stored in an internal RAM. The ASIC can be read out by token ring to reduce the number of lines in the detector. More than 1.3 million ASIC will be necessary to read out the whole calorimeter.