Multi-layer dual-energy detectors with fiber optic faceplate

Abstract

Sandwich-like multilayer detectors can measure dual-energy images at a single x-ray shot and the resulting images are free from the motion artifacts. In case of phosphor-coupled photodiode detector-based multilayer detectors, the direct x-ray interaction within the front photodiode layer can be a significant noise source. In this study, we propose to use a fiber-optic faceplate (FOP) between the front phosphor and photodiode layers, instead of the intermediate metal filter between the front and rear detector layers. This detector design is based on the fact that the FOP can reduce the probability of direct interaction of x-ray photons with the front photodiode as well as prevent x-ray photons with lower energies from reaching the rear detector layer. We develop a cascaded-systems model to describe the signal and noise characteristics in multilayer detector designs with the FOP. With the developed model, we investigate the imaging performance of the proposed detector designs for various FOP thicknesses in comparisons with the experimental measurements. The cascaded-systems analysis and demonstration dual-energy images of a postmortem mouse show that the proposed design is feasible for dual-energy imaging.