Cryo X-ray Microscopy

The technique bridges the resolution gap that exists between electron microscopy and conventional light microscopy and allows acquisition of tomographic data from both native and fluorescent-labelled samples. So far we have the most experience with collecting data on cells grown adherently on 3mm grids (as used in electron microscopy) but we have also collected data on bacteria and structures containing lipidic networks. The common theme is that all samples are mounted on 3mm EN grids and vitrified in liquid nitrogen cooled liquid ethane.

At present B24 is operating at 500eV (in the “water window”) where the image contrast is generated by the preferential absorption of the X-rays by carbon with the surrounding water/ice is relatively transparent. In due course operation of the beamline will extend outside the water window particularly to higher energies. This should allow data to be collected either side of an absorption edge so that certain elements within a sample (e.g. Fe) can be highlighted. In addition it is planned to offer Zernike phase contrast at 2.5 keV.