X-ray inspection using wavelength-shifting fiber-coupled scintillation detectors

A detector of x-ray radiation characterized by a thickness and an area, the detector comprising:

• a. a first volume of a first scintillation medium for converting energy of incident x-ray radiation into a first scintillation light;
• b. a first plurality of wavelength-shifting optical waveguides, aligned substantially parallel to each other over a first scintillation light extraction region contiguous with the first volume of the first scintillation medium, for guiding light derived from, and at a first wavelength longer than that of, the first scintillation light;
• c. a second volume of a second scintillation medium for converting energy of incident x-ray radiation that has traversed the first volume into a second scintillation light;
• d. a second plurality of wavelength-shifting optical waveguides, aligned substantially parallel to each other over a second scintillation light extraction region contiguous with the second volume of the second scintillation medium, for guiding light derived from, and at a wavelength longer than that of, the second scintillation light;
• e. a first photo-detector for detecting photons at the first wavelength guided by the first plurality of waveguides and for generating a first detector signal;
• and
• f. a second photo-detector for detecting photons at the second wavelength guided by the second plurality of waveguides and for generating a second detector signal.