Characterization of the TJ-Monopix2 Depleted Monolithic Active Pixel Sensor for High-Energy Physics Experiments

Monolithic pixel detectors demonstrate an advancement in the field of particle detectors, offering high spatial resolution and low material budget. With the availability of highly resistive silicon substrates and high-voltage capabilities, significant depletion can be achieved. Charge collection by drift in the depleted silicon increases the signal strength, response time, and radiation hardness. These so-called depleted monolithic active pixel sensors (DMAPS) are fabricated in one entity of silicon and employ readout electronics within the pixel cell, eliminating the interconnection step of hybrid pixel detectors. <br> The TJ-Monopix DMAPS prototypes follow a design approach where the in-pixel electronics is separated from the charge collection node in the pixel, minimizing the size of the latter and consequently the detector capacitance. This facilitates low-power and low-noise operation with a large signal and fast rise time. Within the scope of this work, the radiation hardness of the revised TJ-Monopix1 sensor geometry has been studied. The chip exhibits a hit detection efficiency above 98 % after a NIEL fluence of 10¹⁵ n_eq cm^-2, depending on the exact implementation. The limiting factor could be identified as the minimum achievable detection threshold compared to the signal height. <br> TJ-Monopix2 is the latest iteration in the TJ-Monopix prototype series and is the result of a significant effort to improve the front-end performance and include more digital logic into the chip that is responsible for configuration and communication. The development of the latter is covered in this thesis and the custom data acquisition system is presented. The revised front-end electronics enables operation at a significantly lower threshold than TJ-Monopix1. As a result, test beam measurements show a hit detection efficiency of up to 99.96 % of which 99.7 % are detected within 25 ns. A time resolution of the front-end electronics of 100 ps can be achieved at a power consumption of less than 1 μW per pixel for the analog circuitry. In summary, the findings in this thesis demonstrate a good hit detection efficiency and excellent timing performance of the TJ-Monopix2 DMAPS prototype and shows its suitability for high-energy physics experiments.