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A lithium fluoride (LiF) crystal has been utilized as a new soft X-ray detector to image different biological samples at a high spatial resolution. This new type of image detector for X-ray microscopy has many interesting properties: high resolution (nanometer scale), permanent storage of images, the ability to clear the image and reuse the LiF crystal, and high contrast with greater dynamic range. Cells of the unicellular green algae Chlamydomonas dysosmos and Chlorella sorokiniana, and pollen grains of Olea europea have been used as biological materials for imaging. The biological samples were imaged on LiF crystals by using the soft X-ray contact microscopy and contact micro-radiography techniques. The laser plasma soft X-ray source was generated using a Nd:YAG/Glass laser focused on a solid target. The X-ray energy range for image acquisition was in the water-window spectral range for single shot contact microscopy of very thin biological samples (single cells) and around 1 keV for multishots microradiography. The main aim of this article is to highlight the possibility of using a LiF crystal as a detector for the biological imaging using soft X-ray radiation and to demonstrate its ability to visualize the microstructure within living cells., (2008 Wiley-Liss, Inc.)

High contrast imaging of in vivo Chlorella sorokiniana cells with submicron spatial resolution was obtained with a contact water window X-ray microscopy technique using a point-like, laser-plasma produced, water-window X-ray radiation source, and LiF crystals as detectors. This novel type of X-ray imaging detectors is based on photoluminescence of stable electronic point defects, characterized by high intrinsic resolution. The fluorescence images obtained on LiF crystals exposed in single-shot experiments demonstrate the high sensitivity and dynamic range of this new detector. The powerful performances of LiF crystals allowed us to detect the exudates of Chlorella cells in their living medium and their spatial distribution in situ, without any special sample preparation., (2007 Wiley-Liss, Inc)