Abstract: A radiometric analyzer for measuring the characteristic values of a sample by radiation includes a plurality of radiation measuring subsystems having different ratios of sensitivities to the elements of the sample and linearizing circuits having inverse function characteristics of calibration functions (calibration function while varying the density in a constant content ratio of the sample) which correspond to the radiation measuring subsystems and a weighing adder for operating a desirable linear combination of the outputs of the linearizing circuits and operators for operating between two or more different linear combinations.

Abstract: A radiometric analyzer for measuring characteristics of a material by radiation comprises a plurality of systems in which each consists of a radiation source and a radiation detector which are the same in number as the number of elements of the molecule of the material and a linear calibration circuit having inverse response characteristics (calibration curve) of the respective systems of detectors, whereby the measurement is carried out by a four fundamental rules operation of the mutual outputs of said detector system obtained through said linear calibration circuit. One typical embodiment is a radiometric analyzer for hydrocarbons which measures the density of heavy oil, the sulfur content and the calorific value by three detector systems which include a .gamma.-ray source (E.sub..gamma. > 50 KeV), a soft X-ray source (Ex .apprxeq. 20 Kev), and a neutron ray source.