Imaging systems for the liquid Argon target of SAND at the DUNE Near Detector Complex

The Deep Underground Neutrino Experiment (DUNE) has among its primary goals the determination of the neutrino mass ordering and the possible CP-violating phase in the neutrino mixing matrix. The System for On-Axis Neutrino Detection (SAND) is one of the three components of the DUNE Near Detector complex, permanently located on-axis to monitor the neutrino beam stability and measure its flux. SAND includes a novel liquid Argon detector- GRAIN- designed to image neutrino interactions using scintillation light produced in Ar by charged particles, eliminating the dependence on slow charge collection of LAr TPCs. Two optical systems are currently being developed for GRAIN, both based on Silicon Photomultiplier (SiPM) matrices, coupled either to UV cryogenic lenses or Coded Aperture masks. This contribution will present the design of GRAIN optical systems and their spatial resolution performance in preliminary simulation studies.