Optimization of the X-Arapuca photon collection efficiency for the DUNE horizontal drift far detector
E. Bertolini, C. Brizzolari, F. Bruni, P. Carniti, C. M. Cattadori, S. Copello, E. Cristaldo, M. Delgado, F. Galizzi, C. Gotti, D. Guffanti, A. A. Machado, L. Malinverni, L. Meazza, F. Meinardi, G. Pessina, G. Raselli, M. Rossella, E. Segreto, H. Vieira de Souza, F. Terranova, D. WarnerAbstract
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