Optimization of the X-Arapuca Photon Collection Efficiency for the DUNE Horizontal Drift Far Detector

TL;DR

This paper reports on optimizing the X-Arapuca photon collection system for DUNE's Far Detector, achieving an approximately 84% efficiency increase through experimental testing and simulations to enhance long-term detector performance.

Contribution

It introduces an improved X-Arapuca configuration with up to 84% higher efficiency, validated by measurements and simulations, to meet DUNE's long-term operational requirements.

Findings

Achieved up to 84% efficiency increase over baseline design.

Validated the improved design through experimental measurements.

Demonstrated potential for enhanced detector safety margin and physics performance.

Abstract

The Deep Underground Neutrino Experiment (DUNE) Far Detector (FD) Photon Detection System (PDS) employs the X-Arapuca concept, a photon trapping system relying on reflective surfaces and dichroic filters. In this paper are reported measurements, performed at the University of Milano-Bicocca, aimed at increasing the FD Horizontal Drift (HD) PDS module efficiency. The baseline implementation of the X-Arapuca concept for the FD-HD PDS module is close to the DUNE requirements as demonstrated in the collaborations laboratory testing. However, an increased performance would provide a safety margin for a detector planned to be operated for 30 years, without possibility of performing maintenance. A higher detector performance would also benefit the DUNE low energy physics program. The already proven Milano-Bicocca setup has been utilized to test different PDS module configurations comparing them to the original baseline. Exploiting prior knowledge of the X-Arapuca components and Geant4 based optical simulations it has been possible to achieve up to an ~84% performance increase over the baseline design. In the following it is presented the testing procedure, the performed measurements and a brief discussion on the obtained results.