Sem-hosted soft x-ray microscope for live cell imaging

Using soft X-ray radiation in the so called "water window" energy range allows visualizing of cell structure and provides information which is complimentary to information obtained by electron and optical microscopy. Till now all methods for X-ray generation with energies of several hundreds eV were based on synchrotron radiation sources or laser-pumped sources and cannot be used in laboratory environments. To overcome this limitation, an SEM-hosted soft X-ray microscope has been designed using a titanium target to produce 450eV radiation, which is well positioned inside the "water window" between the absorption edges of carbon (present in proteins), and water. Using a special specimen holder to keep the biological sample under normal environmental conditions allows imaging of living cells without any fixation or preparation. An X-ray camera with direct detection performs image acquisition. The suggested set- up was tested in two types of SEM with different electron beam density, showing the possibility of live cell imaging with submicron resolution.