| Summary: | <p>Monolithic active pixel sensors are a viable detector option for many high energy particle physics experiments, as they reduce both the production cost and the amount of material required in a detector. They are produced in CMOS (Complementary Metal-Oxide Semiconductor) processes, which are ubiquitous across consumer electronics and therefore have been the focus of development for several decades. The thesis focuses on a prototype device produced in a 180 nm TowerJazz high resistivity CMOS process, which was initially designed for the ATLAS experiment. Specifically, it investigates the radiation hardness of the sensor by measuring the capacitance of the collection electrode and the depletion region before and after irradiation. There are inefficiencies found at the pixel corners after irradiation, which are also confirmed by previous test-beam campaigns.</p>
<p>A new chip with additional modifications designed to combat those inefficiencies
was produced. A novel measurement using an X-ray test-beam was conducted to
measure the effect of the new modifications. It was found that they reduce the
corner inefficiencies after irradiation. Furthermore, an extrapolation technique was
used to compare and contrast the results from the X-ray test-beam with conventional
charged particle test-beam done on the same chip.</p>
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