The Gamma-Ray tool measures the naturally occurring Gamma Radiation from the surrounding rock formation. This is the amount of gamma radiation emitted by the formation surrounding the borehole. The most abundant source of gamma radiation is potassium-40 (K40) and daughter products of the uranium- and thorium-decay series.
Clay-bearing rocks commonly emit relatively high gamma radiation because they include weathering products of potassium feldspar and mica and tend to concentrate uranium and thorium by ion absorption and exchange.
The vertical resolution of the gamma-ray sensor is approximately 1 foot. The larger the cross-section of the detector (and its length) determines the efficiency of the detection system.
The sizes we use are 2” x 4” and 1.75” x 8” crystals, providing excellent counting rates and repeatability.
A Gamma-Ray survey is extremely useful as a correlation log with other logs such as the Elog or Laterolog.
Click on thumbnail for a larger image of the GAMMA-RAY/SPECTRAL
PDF of GAMMA-RAY/SPECTRAL