A new front-end electronics chain for timing RPCs

Recent advances in electronics and counter construction techniques have pushed the timing resolution of resistive plate chambers below 50 ps sigma, with a detection efficiency of 99% for minimum ionizing particles. In this paper, we describe a new front-end electronic chain for accurate time and charge measurement in these devices. The circuit includes a fast (2.5 GHz) two-stage amplifier based on monolithic microwave integrated circuits that feeds a fixed threshold discriminator followed by an external time-to-digital converter. The amplified signal is also buffered into an external charge-to-digital converter. All components are commercially available and their number is rather reduced. The system was tested with realistic detector-generated test signals, yielding a timing resolution around 10 ps sigma for signal charges above 100 fC and a charge resolution of 3.2 fC.