Dictionary:Gamma-ray spectroscopy log
1. A log of natural gamma-radiation intensity within discrete energy bands that are characteristic of specific radioactive series. Differs from the conventional gamma-ray log that measures broad-spectrum, undifferentiated gamma energy. Useful for correlation where other methods fail, and also useful for uranium exploration where potassium or minerals in the thorium series contribute significantly to total gamma radiation. The natural gamma-ray spectroscopy log looks at several energy windows to identify the natural radiation from potassium (40K), uranium (238U), and thorium (232Th). It is useful in identifying clay content where other radioactive minerals are present. Also called spectral gamma-ray log. 2. The induced gamma-ray spectroscopy log involves bombardment by high-energy (14 MeV) neutrons that causes elements to emit gamma rays of characteristic energy. Also called neutron activation log.