Abstract

The X-ARAPUCA is a device for the detection of scintillation light in liquid argon and represents an evolution of the ARAPUCA design, with an increased collection efficiency and a simpler design. The first liquid argon test of an X-ARAPUCA prototype has been performed in the cryogenic facility of the Laboratorio de Leptons da UNCIAMP and showed a detection efficiency of 3.5% +/- 0.5%, in line with the expectations from Monte Carlo simulations and extrapolations from measurements with standard ARAPUCAs.