Speaker
Description
MOSAIX is a full-scale full-size monolithic CMOS pixel sensor prototype developed for the ALICE Inner Tracking System 3 (ITS3), which will replace the three innermost layers of the ALICE tracker during the LHC Long Shutdown 3 (LS3). With over 26 cm in length and 2 cm in width, it contains 12 repeated sensor units (RSU) containing each 12 pixel matrix tiles of 22.8 x 20.8 µm2 pixels. Power supply and data lines of each RSU are connected by stitching to the the power pins on the left and right end cap and to the readout processor in the Left End Cap, respectively. MOSAIX is designed to operate with air cooling only, and redefines the limits of monolithic CMOS pixel detectors - spanning an entire wafer while maintaining over 99% pixel detection efficiency and a fake hit rate of 10-6 hits/pixel/event. Thinned to 50 µm and integrated with carbon foam only, it presents a material budget of 0.09% X0 per layer. Developing an ASIC this size introduces challenges that go beyond traditional ASIC design. Wafer production failures, no longer confined to individual dies must be addressed by design across the entire stitched wafer. The architecture addresses this by implementing the sensor as a distributed system, where repeated processing units are integrated into a continuous structure and maintained through localized control and fault isolation. With all power and data IO connections constrained to the short edges, the system must sustain over 30 Gb/s of throughput while remaining below 40 mW/cm². This presentation will show how architecture, yield resilience, and power distribution management converge in MOSAIX, illustrating the design principles behind one of the most ambitious wafer-scale detectors built to date.
