An apparatus and method is presented for controlling the quality of a mass
density measurement of a multiphase fluid mixture including a plurality
of fluid fractions and a plurality of constituting elements. The method
includes the steps of: submitting a measuring pipe to a flux of high
energy photons and measuring count rates; determining a mass density of
the multiphase fluid mixture based on count rate measurements in a first
and second energy windows; determining an electronic density of the
multiphase fluid mixture based on count rate measurements in a third
energy window; and comparing the electronic density to the mass density
of the multiphase fluid mixture.