A novel optical imaging system for the LAr detector GRAIN

Abstract

The Deep Underground Neutrino Experiment will be a next generation neutrino oscillation long-baseline accelerator experiment exploiting Liquid Argon Time Projection Chambers with the aim of determining the still unknown neutrino oscillation parameters, observing proton decay and detecting supernova neutrinos. GRAIN (GRanular Argon for Interactions of Neutrinos) is the Liquid Argon detector of SAND (System for on-Axis Neutrino Detection), which is part of the DUNE Near Detector complex. SAND is expected to significantly decrease uncertainties related to neutrino flux and cross-sections, to monitor the beam stability, and to investigate various neutrino interactions models, constraining at the same time nuclear effects. GRAIN will serve as a Liquid Argon target for detecting neutrinos and low-energy particles, ensuring cross-calibration with the other Near Detector components. The novel GRAIN system is designed to reconstruct charged particle tracks using the detection of LAr scintillation light by an optical system optimised for the Vacuum Ultra-Violet. Two options for the optical system are currently being studied: coded aperture masks and optical lenses, both coupled to a SiPM matrix. The readout, which is currently under development, will be performed through a 1024-channel ASIC, able to read 32x32 SiPM matrices in LAr