Characterization of monolithic CMOS pixel sensors for charged particle detectors and for high intensity dosimetry

I have studied the characteristics of two CMOS Monolithic Active Pixel Sensors chips and tested them under different front end configuration. The first chip, the TJ-Monopix1 from the Monopix series initially developed for ATLAS ITK by the R&D collaboration, is one of the prototypes for the Belle II vertex detector upgrade. The second chip, called Main Demonstrator-1 is designed by the ARCADIA (Advanced Readout CMOS Architectures with Depleted Integrated sensor Arrays) group; it is intended to be a general purpose device with possible use in medical scanners, space experiments, future lepton colliders and also possibly X-ray applications with thick substrates. A possible new application of Monolithic Active Pixel that I have investigated is the use in dosimetry: in the last few years the search of radiotherapy oncological treatments with high intensity beams (FLASH mode) is requiring new dosimeters, both for the therapies as well as new beam-monitors (especially for focused very high energy electron beams), which are capable of deal with extreme dose rate (up to 40 Gy/s). I have set up the test systems for the two chips in the INFN clean laboratories and characterized the devices electrically and with radioactive sources in terms of threshold, noise, dead time and analog response. As conclusion of the measurement campaign, we have tested TJ-Monopix1 at very high intensity using the electron beam of the new ElectronFlash accelerator designed for both medical research and R&D in FLASH-radiotherapy and recently installed at Santa Chiara hospital in Pisa. I have participated in the design of the setup needed for testbeam measurement and I am currently working on the analysis of the data collected