Efficiency and performance studies of depleted monolithic active pixelated particle detectors

Abstract

Depleted Monolithic Active Pixel Sensors (DMAPS) are particle detectors that combine a sensor and corresponding readout electronics in a single silicon wafer. This detector design is particularly interesting for high-energy physics since it can be fabricated with commercial CMOS technology at a lower cost compared to hybrid pixel detectors. Furthermore, the thin design allows for a low material bud- get, which is essential for applications such as vertex detectors in lepton colliders. This master’s thesis investigates the performance of two flavors with and without radiation damage of those DMAPS, particularly the so-called RD50-MPW4 and the TJ-Monopix2 chips. The RD50-MPW4 chip is a prototype developed by the CERN-RD50 CMOS group. Significant design works were performed in-house at HEPHY in the past. The TJ-Monopix2 chip was created to meet the requirements of the HL-LHC ATLAS ITk upgrade. It is now of particular interest to use for the Belle-II VTX upgrade.For the performance characterization, eight samples of the RD50-MPW4 and two samples of the TJ-Monopix2 were measured at the particle accelerator facility DESY. For unirradiated samples, an efficiency of 99.99 % and a spatial resolution of 16.27μm could be achieved for the RD50-MPW4. For the unirradiated TJ- Monopix2 sample, an efficiency of 99.94 % and a spatial resolution of 9.3 μm could be reached. Reasonable performance could be measured for the RD50-MPW4 ir- radiated up to a fluence of 1 × 1015 neqcm−2 and for the TJ-Monopix2 irradiated up to a fluence of 5 × 1014 neqcm−2.