Resistive AC-Coupled Silicon Detectors: Principles of operation and first results from a combined analysis of beam test and laser data

This paper presents the principles of operation Resistive AC-Coupled Silicon Detectors (RSDs) and measurements temporal spatial resolutions using a combined analysis laser beam test data. RSDs are new type n-in-p silicon sensor based on Low-Gain Avalanche Diode (LGAD) technology, where $n^+$ implant has been designed to be resistive, read-out is obtained via AC-coupling. The truly innovative feature RSD that signal generated by an impinging particle shared isotropically among multiple pads without need for floating electrodes or external magnetic field. Careful tuning coupling oxide thickness doping profile at basis successful functioning this device. Several matrices with different pad width-pitch geometries have extensively tested setup in Laboratory Innovative Sensors Torino, while smaller set devices Fermilab Test Beam Facility 120 GeV/c proton beam. measured resolution ranges between $2.5\; \mu m$ 70-100 pad-pitch geometry $17\; 200-500 matrices, factor 10 better than what achievable binary ($bin\; size/ \sqrt{12}$). data show $\sim 40\; ps$ 200-$\mu pitch devices, line best performances LGAD sensors same gain.