FLUKA Simulation of sFLASH Experiment

The Telescope Array (TA) is the largest cosmic ray detector in the Northern Hemisphere. It consists of a surface detector of plastic scintillation counters overlooked by 3 fluorescence detector sites. TA measures cosmic rays from 1 PeV to 100 EeV and higher by observing extensive air showers in the atmosphere. To determine the shower energy, it is important to understand the fluorescence yield (FY), which is a conversion factor from the energy deposition in air to the fluorescence light. sFLASH is an auxiliary experiment of TA that measures FY in air produced by high energy electrons in an air volume called the active region. In this work, we report the results of a FLUKA simulation of sFLASH to gauge our understanding of the energy deposition in the experiment. We compare our FLUKA simulation results with an alternative simulation that uses Geant4 software, implemented by a different team within the sFLASH collaboration. Preliminary results show that both results agree to within 3%. The sFLASH FY systematic uncertainty will be reduced using the energy deposition of our sFLASH FLUKA simulation. This will improve the energy estimation of the high energy cosmic rays by the experiments such as TA and Auger.