Development of quasi-diffraction-limited resolution lens-coupled X-ray imaging detector

Abstract

X-ray microscopy experiments at synchrotron radiation facilities generally require X-ray imaging detectors with high spatial resolution and a wide field of view. For such purposes, lens-coupled X-ray imaging detectors are widely used. The SPring-8 X-ray microscopy beamlines require detectors that satisfy a 200 nm spatial resolution and over 50 mm field of view. We have demonstrated spatial resolution of 200 nm line-and-space patterns visualization by using photodiffusion-free transparent scintillator. For the field of view, we have carried out a systematic optical design based on an analytical optimization approach and elucidated that a set of five detector systems is able to meet these requirements while keeping near-diffraction-limited spatial resolution. Their objective lenses have magnifications of 20x, 7x, 5.2x, 3.5x, and 1x. All the systems are designed to be equipped with 150 Mpixel CMOS image sensors. To verify our optimization approach, we have built a detector system with a magnification of 3.5x. The detector has successfully resolved 1.2 μm line-and-space patterns for the entire field of view, which is close to the optical diffraction-limited resolving power of 1.0 μm line-and-space patterns.