Optical simulation of LIXO2 using GPUs

Next-generation searches for neutrinoless double-beta decay and dark matter, such as DARWIN and nEXO, will rely on detection of vacuum ultraviolet light in liquid xenon to reconstruct energy of events. Accurate knowledge of the optical properties of photodetectors and materials is essential for optimization of these experiments. LIXO2 is an upgraded setup built at the University of Alabama to characterize the reflective properties of materials and photodetection efficiency of silicon photomultipliers (SiPMs) to be used by the next-generation liquid xenon experiments. Optical simulations of LIXO2 is critical to understand the systematic effects and improve accuracy of the measurements. This talk will describe the LIXO2 optical simulation based on the Chroma framework. Chroma uses GPUs for ultra-fast photon tracking and directly uses CAD files to describe experimental geometry. Studies conducted using this framework will be described.