SSHCZO -- Geophysics -- Gamma Ray Logs -- Shale Hills -- (2010-2010)

Natural gamma ray logs are indicating the concentration of thorium (Th), uranium (U), and potassium (K) in the rocks surrounding a borehole and they are a measurement of the natural radioactivity of the formation. The energy of the gamma-rays (photons) differs for Th, U, and

K. Potassium emits only gamma photons of energy 1.46 MeV. Thorium emits gamma photons of a number of different energies, the highest of which is 2.62 MeV. Uranium similarly emits gamma photons of a number of different energies with 1.76 MeV as the highest energy that can be detected in a borehole. Here the values indicate total gamma ray energy and are function of well depth.