Detective quantum efficiency (DQE)-oriented design of a transparent scintillator tandem x-ray/optical microscope for photon-starved 7.2-keV radiography at the National Ignition Facility (NIF).

X-ray radiography at the National Ignition Facility (NIF) must simultaneously achieve micron-scale spatial resolution and adequate signal-to-noise ratio with a limited number of 7.2-keV photons. To address this coupled resolution-throughput challenge, we developed a scintillator-based x-ray imager using a tandem microscope architecture. A curved Bragg-crystal x-ray microscope forms a magnified 7.2-keV image on a transparent thallium-doped cesium iodide [CsI(Tl)] scintillator, and a visible-light microscope relays the scintillation image to an oversampled complementary metal-oxide-semiconductor (CMOS) detector. This separation of x-ray image formation and optical readout enables high-resolution, quasi-monochromatic x-ray imaging while suppressing lateral light diffusion in the scintillator. We present a component-level model for optimizing detective quantum efficiency (DQE) that includes x-ray absorption, scintillation conversion, optical collection, sensor quantum efficiency, event-yield variance, and CMOS readout noise. Using measured component throughputs, the model conservatively predicts a zero-spatial-frequency DQE DQE0 of ∼32% for a 7.2-keV photon fluence of 2.45×108photonscm-2 incident on the scintillator plane, while integrated measurements demonstrate an object-plane resolution of ∼5 μm. These results provide a quantitative design path for photon-starved, high-resolution x-ray radiography at NIF.