1. n. [Formation Evaluation]

The principle of an activation log, which is a log of elemental concentrations derived from the characteristic energy levels of gamma rays emitted by a nucleus that has been activated by neutron bombardment. The term is often used to refer specifically to the pulsed neutron spectroscopy measurement.

See: activation log,  elemental capture spectroscopy,  geochemical log,  neutron interactions,  pulsed neutron spectroscopy log,  spectrum