Paper detail

Early Results on Radioactive Background Characterization for Sanford Laboratory and DUSEL Experiments

Measuring external sources of background for a deep underground laboratory at the Homestake Mine is an important step for the planned low-background experiments. The naturally occurring $γ$-ray fluxes at different levels in the Homestake Mine are studied using NaI detectors and Monte Carlo simulations. A simple algorithm is developed to convert the measured $γ$-ray rates into $γ$-ray fluxes. A good agreement between the measured and simulated $γ$-ray fluxes is achieved with the knowledge of the chemical composition and radioactivity levels in the rock. The neutron fluxes and $γ$-ray fluxes are predicted by Monte Carlo simulations for different levels including inaccessible levels that are under construction for the planned low background experiments.