Data acquisition systems for depleted monolithic active pixel sensors

Abstract

Silicon detectors play a major role in tracking and vertexing in all major particle collider experiments. In recent years new production techniques in the chip industries allow complementary metal-oxide-semiconductor (CMOS) electronics on high-resistivity substrates and high-voltage compatible processes. In high energy physics, these advancements lead to depleted CMOS monolithic active pixel sensors. The possibility of applying high depletion voltages, which is why this detector type is also referred to as HV-CMOS, and using relatively high-resistivity substrates suits this technology well for high radiation environments. Within this approach, the charge-sensitive collecting electrodes, as well as the front-end electronics, are integrated into the same CMOS wafer. This allows for lower noise, higher sensitivity, and also a reduced material budget compared to standard silicon pixel detectors. The use of the commercial standard CMOS process allows for reduced production costs and, therefore, manufacturing of detectors with a large sensing area is possible. In the context of this master thesis, two HV-CMOS pixel detectors, the RD50MPW3 developed by CERN-RD50 collaboration and the TJ-Monopix2 developed by the ATLAS collaboration and now studied by the Belle-II collaboration for possible upgrades, have been integrated into data-acquisition frameworks consisting of hardware and software components. Within these frameworks called Caribou, BDAQ53 and EUDAQ, the detectors have been tested in a laboratory environment as well as at the particle-accelerator facilities DESY and CERN. The recorded data were analyzed and interpreted in order to quantify the performance of these detector prototypes and to compare them with each other. Moreover, simulations were performed and were compared with the measured results.