Spectral discrimination using wavelength-shifting fiber-coupled scintillation detectors

A method for discriminating among x-ray beams of distinct energy content, the method comprising:

• a. converting energy of an x-ray beam incident upon a first volume of scintillation medium into a first scintillation light;
• b. guiding light derived from, and at a first wavelength longer than the first scintillation light via a first plurality of wavelength-shifting optical waveguides;
• c. converting energy of x-ray radiation that has traversed the first volume into a second scintillation light in a second volume of scintillation medium, wherein the second volume of scintillation medium is a different volume from the first volume of scintillation medium;
• d. detecting, with a first photodetector, photons at the first wavelength guided by the first plurality of waveguides thereby generating a first detector signal;
• and
• e. detecting, with a second photodetector, photons due to scintillation in the second volume of scintillator material thereby generating a second signal;
• f. processing the first signal and the second signal to provide a measure of a low energy component and a high-energy component of the x-ray beam incident upon the first volume of scintillation material.