Application of laser-plasma X-ray source to imaging of living cells and photoelectron micro-spectroscopy

Summary form only given. A laser-plasma based X-ray source (LPX) is not only compact but also highly brilliant, and extremely short in temporal duration. Owing to these characteristics, the source will find applications to open new scientific frontiers. In X-ray contact microscopy (XRM) of imaging living cells in solution, we observed structures of as small as 40 nm diameter. Reasonably high resolution in depth is also obtainable in contact microscopy by recording stereo images, as we demonstrated in our recent experiment. In our stereo imaging, all second exposures later than 40 ns after the first exposure failed to produce image of thin structures, which clearly showed short pulse exposure is crucially important in XRM of living cells. So far, our XRM experiments were done using a big high-power laser system. Very recently, we developed a table-top XRM system using a small commercial Q switch laser. In our new system, motion of specimens to be imaged are observed under an optical microscope, recorded in a magnetic tape until the instant of exposure, and specimens are X-ray exposed at any moment we want. Application of LPX to X-ray photoelectron micro-spectroscopy (/spl mu/-XPS) is also quite promising. Theoretically, the spectrum acquisition speed of the /spl mu/-XPS system with LPX could exceed that with the undulator radiation even in observing steady states. In the observation of intermittent or transient phenomena, any other existing sources can not compete with LPX. Our estimation on the photon flux has been confirmed in preliminary experiments. Chemical shifts of Si were nicely resolved in the photoelectron spectra, and the detected photoelectron number was as large as expected.