Speaker
Description
Precision timing is of the essence in intensity interferometry. Whether the task involves the temporal tagging of single photons or the continuous acquisition of photocurrents over time, measuring the Hanbury-Brown and Twiss effect between distant telescopes necessitates the stable sampling of signals at well-determined times throughout the night of observation. The advent of photodetectors with jitter of a few tens of picoseconds, intended for astronomical intensity interferometry measurements, therefore calls for picosecond-level time synchronisation between clocks separated by several kilometres. The White Rabbit protocol, developed at CERN, is now a standard used in numerous high-energy physics, astroparticle physics and cosmology experiments, enabling time distribution across network nodes with nanosecond-level precision. To achieve picosecond-level precision, engineers at the IJCLab laboratory in high-energy physics have developed and evaluated the IDROGEN carrier board, in close collaboration with metrologists from the LTE laboratory and radio astronomers from the Nancay Observatory. The IDROGEN board is an acquisition platform that integrates an enhanced White Rabbit synchronisation node. The carrier board can be equipped with a 2-channel analog-to-digital converter (1 GS/s, 14 bits per sample), which enables continuous signal sampling. The data transfer rate can currently reach 20 Gb/s, 40 Gb/s capability is under development. This presentation will discuss the timing and sampling performance achieved using IDROGEN boards, and their proposed application to the NectarCAM cameras of the medium-sized telescopes at the Cherenkov Telescope Array Observatory (CTAO).
