The Far Detector of the Deep Underground Neutrino Experiment (DUNE) will be a large LAr
detector located at a baseline of 1300 kilometers, 1.5 km deep underground. It is planned to be
made up of four modules, each with a total mass of 17 kt of LAr, at least the first two of which will
consist in Liquid Argon Time Projection Chambers (LArTPCs). To prove the feasibility of the
LArTPC technology at the kiloton scale, the ProtoDUNE Single and Dual-Phase detectors were
constructed and operated at the CERN Neutrino facility.
This document describes the Vertical Drift detector concept, which is proposed to instrument the
second DUNE module. It consists of a TPC where the electrons drift vertically, with a cathode
suspended at mid-height, towards anodes placed at the bottom and top of the detector. The anodes
would be made out of printed PCBs instead of wires, and the new disposition would allow the top
readout electronics to be accessible during the lifetime of the experiment. An enhanced photo-detection system is also proposed, with the photo-sensors placed on the cryostat walls and the
cathode, but posing a challenge in terms of power and signal transmission. Studies are ongoing
both to overcome the technical challenges of this new design and to finalize the concept.