# Review of Liquid Argon Detector Technologies in the Neutrino Sector
## 2 Single-Phase Experiments
### DUNE (Single-Phase Far Detector)  
The culmination of over 40 years of worldwide research and development of LArTPC technology is Deep Underground Neutrino Experiment (DUNE) [45]. This project is a long-baseline experiment utilising a neutrino beam produced at Fermilab, a near detector complex located 575 m from the beam target, and a far detector complex 1300 km away and 1.5 km underground at the Sanford Underground Research Facility (SURF) in South Dakota. The near detector is expected to implement a variety of technologies [46], including a LArTPC based on the in-development ArgonCube modular TPC and pixelated charge readout systems (described in Section 2.7 below). The DUNE far detector complex at SURF is shown in Figure 21. At the heart of the facility will be four LArTPCs (referred to as \"modules\"), each measuring 14.0 \(\times\) 14.1 \(\times\) 62.0 m and containing approximately 17,500 tonnes of LAr [45]. The first module to be constructed will use the standard single-phase design (referred to hereafter as \"DUNE-SP\", and described in this section). Moreover, the construction of a dual-phase module (\"DUNE-DP\", described in Section 3.1) is also planned. The technology to be implemented in the remaining two modules is yet to be decided. It must be noted that, while the Physics, engineering and operational requirements of the DUNE modules are well understood, their designs are still technically conceptual. Ongoing development, testing and refinement of these designs is being carried out primarily at the single-phase (ProtoDUNE-SP) and dual-phase (ProtoDUNE-DP) ProtoDUNE experiments (described in Sections 2.6 and 3.2 respectively). These detectors use the same designs, technologies and manufacturing and assembly procedures to DUNE-SP and DUNE-DP, allowing all aspects of the experimental hardware and operation to be tested under effectively the same conditions as will be faced by DUNE. A side-on view of DUNE-SP is shown in Figure 22. Much like ICARUS T600, the module will be comprised of multiple drift volumes-in this case, four, with the two CPAs  
Figure 20: Two-dimensional views of a stopping muon and associated Michel electron, as recorded by the LArIAT induction and collection wire planes. Taken from [44]. on consideration of the large total energy (\(\approx\)400 J) stored in the electric field created by such a large-area cathode. In the event of a discharge, the low surface resistivity of a metal cathode would allow all of this energy to be released within nanoseconds, inducing currents in the APA wires that could be high enough to cause damage in the readout electronics. However, Kapton has a high surface resistivity, which reduces the speed of energy dissipation enough to protect surrounding detector components [47]. To preserve the flatness of each CPA across its entire surface, the FR4 sheet of a single assembly is divided into 300 1.2 \(\times\) 2 m \"RP elements\", mounted to a frame also constructed of FR4 (so that both frame and sheet experience the same amount of thermal contraction under cryogenic conditions). Figure 23 (left) shows a section of one CPA, assembled for use in ProtoDUNE-SP but following the same design as will be used in DUNE-SP. As previously noted in Section 2.3, the DUNE-SP (and ProtoDUNE-SP) field cage follows the same design that is currently being implemented in SBND: a structural framework (which, in DUNE-SP, will be constructed from purltruded fiber-reinforced polymer beams) covering the top, bottom and end sides of each module, onto which are mounted rolled aluminium profiles [47]. This design has been chosen primarily for reasons of scale: it is impractical for a detector as large as DUNE-SP to utilise continuous field cage loops such as those on ICARUS T600 and MicroBooNE. A view of one of the ProtoDUNE-SP field cage endwalls is shown in Figure 23 (right).