The DUNE Photon Detection System

The DUNE experiment, currently under construction in the US, has a broad physics program that spans from oscillation physics at the GeV scale to the observation of solar neutrinos in few-MeV events. This program leverages the unprecedented resolution and imaging capability of the liquid argon TPC. LArTPCs are dense, fully-active detectors, that allow for a 3D real-time reconstruction of the events, achieved by means of the collection of drifted electrons from ionization. In addition to electrons, LArTPCs produce large quantities of VUV photons, which will be fully exploited in DUNE thanks to its Photon Detection System (PDS). The light collected by the PDS will be of paramount importance to measure the event timing and the vertical trajectory of charged particles for non-beam events, and will improve significantly the overall energy resolution of DUNE, especially at low energies, allowing to unlock its full scientific potential. The last few years marked important steps in the development of the PDS. Thanks to an intense R&D effort conducted at the two ProtoDUNE detectors at CERN, the PDS technology for DUNE has been optimized and validated for the DUNE physics. This article illustrates the concept of the DUNE PDS, its development and use in ProtoDUNE, as well as its role in achieving the physics goals of DUNE.