First Coupling of AC-LGAD Sensors to a Timepix3 Chip

Since their introduction in 2015, AC-coupled Low Gain Avalanche Diode (AC-LGAD) sensors have attracted wide-spread interest in the scientific community for their ability to provide high spatial resolution while keeping the excellent timing capabilities typical of standard (DC-)LGAD sensors. This is achieved in AC-LGADs because the signal from particle interactions is capacitively induced on fine-pitched electrodes placed over an insulator and is shared among multiple electrodes. AC-LGADs are therefore considered as promising candidates for future detectors such as EIC to provide 4-dimensional measurements with high resolution in both space and time dimensions. AC-LGAD sensors designed and fabricated at the Brookhaven National Laboratory (USA) have been coupled to Timepix3, a pixel detector read-out chip for X-ray imaging and particle track reconstruction developed by the Medipix3 collaboration, offering pixel-level threshold adjustment on a 256x256 pixel matrix and high precision Time-of-Arrival and Time Over Threshold measurement of incoming particles. Three different AC-LGAD strip detectors, custom designed to fit the Timepix3 chip specifications, have been bonded onto a single Timepix3 chip. Studies of the electrical coupling of the two systems and the characterization of AC-LGAD signals readout by the Timepix3 chip are discussed in this work.