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 γ s ⁻¹. The arithmetic mean was 49 γ s ⁻¹ for measurements taken without a collimator. The average gamma flux inside the Lab was 0.25 γ cm ⁻² s ⁻¹. The sedimentary rocks surrounding the Lab are characterized by low activity concentrations of uranium and thorium, equal to 1.7 and 1.4 Bq kg ⁻¹, respectively.