Test of X–ARAPUCA through Monte Carlo simulation in Brazil

Abstract

DUNE is a massive experiment for the study of neutrinos physics which uses liquid argon as active medium. The X-ARAPUCA is a novel technology for the detection of liquid argon scintillation light with an increased detection efficiency with respect to more standard solutions. The X-ARAPUCA light collection efficiency depends on several parameters: the Quantum Efficiency of the active photo-sensitive device, the transmissivity, and reflectivity of the dichroic filter, the shifting efficiency of the wavelength shifters, the reflectivity and shape of the box. The collection efficiency of the device can be maximized by optimizing all of these factors. The present work deals with the Monte Carlo simulation of an experimental set-up which is being used to estimate the total detection efficiency of an X-ARAPUCA. The experiment is constituted by a stainless steel cylinder which hosts the device to be tested and an alpha source. The cylinder is filled with ultra-pure liquid argon and the X-ARAPUCA detects the scintillation photons produced by the alpha particles. The comparison of the experimental spectrum of the detected number of photons with the Monte Carlo spectrum of the number of photons impinging on the X-ARAPUCA acceptance window allows to determine its total detection efficiency. The simulation is based on the GEANT4 package.