Fluorescent lithium fluoride detectors for lensless projection imaging by synchrotron white X-rays

We present broadband X-ray lensless projection imaging experiments performed at the TopoTomo beamline of the ANKA synchrotron facility by using innovative solid-state detectors based on the formation of stable photoluminescent colour centres (CCs) in lithium fluoride (LiF) films and crystals. The peculiar features of these detectors, like very high spatial resolution (standard 250 nm) across a large field of view (> 1 cm2), wide dynamic range (> 103), versatility and easiness of use combined with the high sensitivity of the optical fluorescence microscopy reading technique, make them very attractive as recording plates for X-ray imaging. High-resolution X-ray images of a metallic test pattern were recorded and acquired with good contrast both in LiF crystals and thin LiF films. The stored CCs fluorescence images show edge-enhancement effects ascribable to diffraction processes occurring during the X-ray beam propagation after its interaction with the samples. The experimental data concerning films and crystals based LiF-detectors will be discussed and compared with computer simulations of X-ray intensity distributions. The LiF film performances are very encouraging for the exploitation of these solid-state detectors for X-ray lensless imaging applications.