An X-ray Compton scatter method for density measurement at a point within an object

A non-rotating method for non-intrusively determining the electron density at a point embedded within an object, without full imaging, is presented. Advantage was taken of the multienergetic nature of X-ray photons to devise a dual energy-group multiple-detector scattering scheme for density determination. A measurement model that relates the density of the object to the detector response was formulated, then inverted to determine the electron density at the monitored point. Normalization factors were calculated to compensate for the wide energy distribution of the X-ray photons, and account for other system parameters. In addition, the spread in the source and detectors fields-of-view was accommodated by calculating in advance the volume of the inspection voxel. The method was experimentally applied to a variety of geometries and materials, showing that the electron density can be calculated with a reasonable uncertainty.