The technique can be described as follows. The sample is continuously irradiated with a beam of neutrons. The constituent elements of the sample absorb some of these neutrons and emit prompt gamma rays which are measured with a gamma ray spectrometer. The energies of these gamma rays identify the neutron-capturing elements, while the intensities of the peaks at these energies reveal their concentrations. The amount of analyte element is given by the ratio of count rate of the characteristic peak in the sample to the rate in a known mass of the appropriate elemental standard irradiated under the same conditions.