A scalable gigabit data acquisition system for calorimeters for linear collider

This article presents the scalable Data Acquisition (DAQ) system that has been designed for prototypes of ultra-granular calorimeters for the International Linear Collider (ILC). Our design is generic enough to cope with other applications with some minor adaptations. The DAQ is made up of four different modules, including an optional concentrator. A Detector InterFace (DIF) is placed at one end of the detector elements (SLAB) holding up to 160 ASICs. It is connected by a single HDMI cable which is used to transmit both slow-control and readout data over a serial link 8b/10b encoded characters at 50 Mb/s to the Gigabit Concentrator Card (GDCC). One GDCC controls up to 7 DIFs, distributes the system clock and ASICs configuration, and collects data from them. Each DIFs data packet is encapsulated in Ethernet format and sent out via an optical or copper link. The Data Concentrator Card (DCC) is a multiplexer (1 to 8) that can be optionally inserted between the GDCC and the DIFs, increasing the number of managed ASICs by the GDCC. Using a single GDCC and 7 DCCs allows a single PC to control and readout up to 8960 ASICs (~ 500000 channels). The fourth card is the Clock and Control Card (CCC) that provides a clock and control fan-out to up to 8 GDCCs and therefore to the entire system. A software suite (named Calicoes) written in C and Python manages the overall system. This system have been used for several tests on the Silicon-Tungsten Electromagnetic Calorimeters (SiW-ECAL) prototype detector (1800 channels). The full design and test results will be detailed.