Gamma background measurements in the Gran Sasso National Laboratory

Abstract In situ gamma-ray measurements were taken at eight locations in the Gran Sasso National Laboratory (Italy). Count rates for gamma radiation within the energy range of 7–2,734 keV varied from 8 to 60 c s-1. The arithmetic mean was 49 c s-1 for measurements taken without a collimator. The average gamma flux inside the Lab was 0.25 c cm-2 s-1. The sedimentary rocks sur-rounding the Lab are characterized by low activity con-centrations of uranium and thorium, equal to 1.7 and 1.4 Bq kg-1, respectively