PoF and SoF for the DUNE VD PDS

The Deep Underground Neutrino Experiment (DUNE) is a next-generation long-baseline neutrino oscillation experiment in the US. It consists of four far detector modules, each of which will hold 17 kilotons of liquid argon. These modules sit 1500 meters underground and 1300 kilometers from the near detector complex. The near detector complex will be located at Fermilab about 60 meters underground and 600 meters downstream of the proton beam target.

The first two far detectors will be liquid argon time projection chambers. In the second module (FD2), ionized electrons will drift vertically from a cathode plane suspended at mid-height towards anode planes placed at the top and bottom of the detector volume. For this reason, DUNE FD2 is also called the Vertical Drift (VD) module.

Photon detectors called xARAPUCA will be installed for the first time on the VD cathode plane to provide efficient photon detection. The cathode plane is biased at a very high voltage relative to the anode planes and the potential of the cryostat. In this configuration, it's impossible to electrically transmit readout electronics power and photon signals via conductive cables. A new solution based on optical fiber transmission in liquid argon (LAr) temperature is proposed, demonstrated, and optimized at the CERN neutrino platform cold box. In this talk, I will introduce the power over fiber (PoF) and signal over fiber (SoF) technologies developed for the DUNE VD photon detection system (PDS). I will also summarize the PDS performance at CERN cold box, its status in ProtoDUNE-VD, and the final design for DUNE VD.