ArgonCube: a Modular Approach for Liquid Argon TPC Neutrino Detectors for Near Detector Environments

Liquid Argon Time Projection Chambers (LAr TPCs) are an ideal detector candidate for future neutrino oscillation physics experiments, underground neutrino observatories and proton decay searches. A large international project based on this technology is currently under consideration at the future LBNF/DUNE facility in the United States. That particular endeavor would be on the very large mass scale of 40~kt. Following diverse and long standing R\&D work conducted over several years, with contributions from international collaborators, we propose a novel LAr TPC based on a fully-modular, innovative design, ArgonCube. ArgonCube will demonstrate that LAr TPCs are a viable detector technology for high-energy and high-multiplicity environments, such as the DUNE near detector. Necessary R\&D work is proceeding along two main pathways; the first, aimed at the demonstration of modular detector design and the second, at the exploration of new signal readout methods. This two-pronged approach has provided a high degree of flexibility while being cost-effective and less prone to false negatives. Given the availability of a large cryostat in Bern, the initial effort is concentrated there with help from foreign collaborators. A pixelated, multiplexed charge readout has already been successfully demonstrated along with a new, cold, SiPM based light readout. Upon design, construction and basic operations testing completion, the prototype detector and cryostat will be moved to the Neutrino Platform facility at CERN for a complete engineering and physics test program including exposure to charged particle beams to evaluate detector performance in a higher flux, non-cosmics setting. While the current phase of ArgonCube is mainly taking place in Bern, we are seeking recognition of the ArgonCube project as part of the CERN neutrino platform. CERN recognition would be necessary in order to access resources, both infrastructure and expertise, culminating in ArgonCube test beam studies.