A Radiation-Tolerant Readout System for the ALICE Inner Tracking System Upgrade

During the LHC Long Shutdown in 2019/20, the ALICE collaboration will upgrade various detector sub-systems including the Inner Tracking System (ITS) based on Monolithic Active Pixel Sensor (MAPS) technology. The part of the upgraded ITS readout system installed in the experimental hall consists of 192 custom FPGA-based readout units that control and monitor the sensors and their power supply modules, receive the trigger and detector control information, and deliver the sensor data to the counting room. In this article, we will describe the requirements, the readout concept, the developed prototype boards, and the testing efforts to determine the system susceptibility to the expected radiation levels. In various beam tests with the readout prototypes it was determined that a readout system based on an SRAM FPGA with appropriate protection measures in both hardware and firmware can be successfully operated in the radiation environment expected.