First Demonstration of Imaging Cosmic Muons in a Two-Phase Liquid Argon TPC using an EMCCD Camera and a THGEM

TL;DR

This paper demonstrates the first successful imaging of cosmic muons in a two-phase liquid argon TPC using an EMCCD camera and a THGEM, showing potential for future neutrino experiments.

Contribution

It introduces a novel method of capturing cosmic muon images in a liquid argon TPC with an EMCCD camera and THGEM, enabling new imaging capabilities.

Findings

Successful imaging of cosmic muons with EMCCD in LAr TPC

Achieved clear images at specific gain settings

Performed preliminary 3D muon track reconstruction

Abstract

Colossal two-phase Liquid Argon Time Projection Chambers (LAr TPCs) are a proposed option for future long-baseline neutrino experiments. This study illustrates the feasibility of using an EMCCD camera to capture light induced by single cosmic events in a two-phase LAr TPC employing a THGEM. An Andor iXon Ultra 897 EMCCD camera was externally mounted via a borosilicate glass viewport on the Liverpool two-phase LAr TPC. The camera successfully captured the secondary scintillation light produced at the THGEM holes that had been induced by cosmic events. The light collection capability of the camera for various EMCCD gains was assessed. For a THGEM gain of 64 and an EMCCD gain of 1000, clear images were captured with an average signal-to-noise ratio of 6. Preliminary 3D reconstruction of straight cosmic muon tracks has been performed by combining the camera images, PMT signals and THGEM charge data. Reconstructed cosmic muon tracks were used to determine THGEM gain and to calibrate the intensity levels of the EMCCD image.