The iFTDC front-end cards for the COMPASS and AMBER experiments

Abstract The iFTDC front-end cards were originally developed for the COMPASS experiment, and were later adapted for the streaming readout of AMBER. AMBER is the successor to the COMPASS experiment at the M2 beam line at CERN. This development provides a modern solution for time measurements with a hit rate of up to 1 MHz per channel and a timing precision of 150 ps. The iFTDC is a simple, flexible, and low-cost front-end card designed to measure the timing of signals from various detector types. It is based on an Artix-7 field-programmable gate array (FPGA), it provides 64 channels with LVDS inputs, as well as several user IO pins for configuring attached application-specific-integrated circuits (ASICs). The FPGA's built-in high-speed serial link connects the card to the data acquisition (DAQ) system via the Unified Communication Framework protocol or Ethernet. The Ethernet interface is useful for small-scale experiments and tests in laboratories. In addition to the TDC functionality, each channel includes a scaler. These scalers are used to optimize detector parameters, such as threshold and position, and to monitor detector operation independently of the DAQ. The robust and flexible firmware can be adapted to a wide range of applications requiring precise time measurements. This paper discusses the architecture and performance of the iFTDC card.