Large volumes of liquid argon or xenon constitute an excellent medium for the detection of neutrino interactions and for dark matter searches. The established readout method for large noble liquid detectors is based on charge collection in a time projection chamber, triggered by the scintillation light produced by Ar (128 nm) or Xe (185 nm). This scintillation light can however also be used to attempt a direct reconstruction of charged particle tracks, provided the photon sensor has imaging capabilities. The primary benefit of this technique is rate capability, especially relevant for the near detectors of accelerator based experiments.
Designing such an imaging detector presents several challenges: the performance of both photon detectors and conventional optical elements in the deep UV is limited; thousands of photosensor channels in dense matrices must be operated in cryogenic conditions; and the optical system must provide a sufficiently wide and deep field of vision to maximize the fiducial volume. Through the use of Coded Aperture Masks and SiPM matrices, we have developed a "camera" system that addresses the aforementioned issues and is able to obtain directly a 3D map of the deposited energy with a custom image reconstruction algorithm, which is based on a probabilistic, combinatorial approach.
In this talk, it will be presented one of the proposed designs that employs such cameras for the GRAIN (GRanular Argon for Interactions of Neutrinos) subdetector, a ~1 ton liquid argon cryostat to be installed in the SAND apparatus (System for on-Axis Neutrino Detection) of the Near Detector of the DUNE experiment. Simulations of the detector's imaging capabilities for reconstruction of neutrino events, and the first camera prototypes under construction will be presented as well.
Zoom Coordinates: https://cern.zoom.us/j/98768015328, pass 092020