The ARAGORN front-end. FPGA based Time-to-Digital Converter with superior optical readout capabilities

The ARAGORN front-end offers high-performance readout capabilities for state-of-the-art high-energy physics experiments. The design constraints aim to develop a cost-effective, fully configurable Time-to-Digital Converter (TDC) platform with considerable channel density at smallest form factor possible, allowing for precise time-of-flight or drift-time measurements. The front-end module employs 4+1 Xilinx Artix-7 FPGAs, four of which implement the TDC feature processing a total of 384 channels with an average time resolution of 165 ps. The acquired data is passed on to the fifth on-board FPGA acting as data hub and generic master for auxiliary board components. The board has been designed to set up a multi-tiered optical readout network. Therefore, a SFP transceiver socket for data output and a CXP compliant receptacle reside on the ARAGORN front-end to optionally enable fiber-optic communication with up to seven boards through a star topology. The hot-pluggable CXP module connects to the satellite boards through an optical breakout cable. This novel approach permits to read out in total eight boards yielding 3072 input channels via a single optical fiber at a bandwidth of 6.6 Gb/s.