AC-coupled Low Gain Avalanche Diode Sensors with Long Strip Readout Electrodes

In AC-coupled Low-Gain Avalanche Diode (LGAD), signals produced by charged particles in the silicon sensor active volume are amplified via an internal p+ gain layer near the sensor surface. Signals induced on a continuous resistive n+ layer on top of the p+ gain layer, are AC coupled to patterned metal readout electrodes, which are on the sensor surface and separated by a dielectric layer from the n+ layer. The internal signal amplification and thin active volume enables precise timing measurement, while charge sharing among neighboring electrodes can provide precise position measurement. The AC-LGAD technology has been suggested to use for particle identification, tracking, and far-forward detectors at Electron Ion Collider where precision timing and spatial measurements are needed. For some of these applications, the detector material budget has to be kept at a minimum in order to minimize the multiple scattering effect. AC-LGAD sensors with long strip readout electrodes are proposed to meet these requirements. In this presentation, we will present the first measurement results on AC-LGAD sensors with long strip readout electrodes that were fabricated by Brookhaven National Laboratory. Future plan on optmizing the sensor performance will also be discussed.