Developing 4D Tracking Technology Using Centimeter-Scale AC-LGAD Sensors and the FCFD ASIC

We present the results of studies aimed at developing 4D tracking technology for a wide range of physics experiments, including the Electron Ion Collider (EIC) and future Lepton Colliders. The studies focused on evaluating the performance of centimeter-scale AC-LGAD (AC-Low Gain Avalanche Detector) sensors and a new ASIC (Application-Specific Integrated Circuit) called the Fermilab Constant Fraction Discriminator (FCFD). For the AC-LGADs, we present the resolutions obtained with several prototypes, which reach simultaneous resolutions of 18 microns and 32 ps from strips of 1 cm length and 500 micron pitch. Regarding the FCFD, the mean time response for a wide range of signal amplitudes has been measured to be no more than 15 ps. This is orders of magnitude more precise than an uncorrected leading-edge discriminator-based measurement and effectively eliminates the need for a signal amplitude-based correction. Furthermore, the measured contribution to the time resolution from the FCFD ASIC is found to be 10 ps for signals with charges above 20 fC.