Speaker
Description
The Deep Underground Neutrino Experiment (DUNE) seeks to address key questions in particle physics, including neutrino mass ordering, CP violation in the lepton sector, and searches for proton decay and supernova neutrinos. Central to these objectives is the Photon Detection System (PDS), which captures scintillation light for precise event timing, calorimetry, and triggering.
The DUNE horizontal drift (DUNE-HD) PDS uses X-ARAPUCA technology, with detectors positioned behind the transparent wired Anode Plane Assemblies (APA). In contrast, DUNE vertical drift (DUNE-VD) utilizes Charge Readout Planes (CRP) for charge detection, which have reduced transparency, requiring photon detectors to be placed on the cathode and behind the field cage. The DUNE-VD features large X-ARAPUCA detectors in both locations, providing extensive optical coverage (~4π) and enhancing photon detection uniformity. The placement of detectors on the cathode was enabled by the pioneering development of Power-over-Fiber (PoF) and Signal-over-Fiber (SoF) technologies for liquid argon. These innovations provide essential electrical isolation and noise immunity, which are critical for the high-voltage cathode-mounted design. Successful validation of this approach through tests at CERN and Fermilab represents a significant milestone for the DUNE-VD project.
In DUNE's Phase II, the APEX (Aluminum Profiles with Embedded X-ARAPUCAs) concept is proposed for the third detector module. This innovative system leverages PoF and SoF technologies developed for DUNE-VD PDS, embedding photon detectors directly into the field cage profiles. This design ensures 100% coverage on four sides of the detector, achieving approximately 60% optical coverage overall. APEX is expected to significantly enhance light yield and uniformity. This increased light collection capability for MeV-scale energy deposits, along with improved energy reconstruction up to the GeV scale, positions APEX as a key component in helping DUNE achieve its long-term physics objectives. Promising results from simulations and prototypes at CERN support the potential of this approach.
