Comparison of laser-generated plasma x-ray sources for contact microscopy

Soft x-ray contact microscopy (SXCM) is a technique which can image the ultrastructure of living biological specimens at a resolution considerably better than light microscopy (LM). Two such laser systems have been developed for the generation of water window x rays. A small beam line of the large Nd:GLASS laser `Vulcan' at the Rutherford Appleton Laboratory (RAL), UK, has been set up, giving approximately 6 - 8 J on target at a wavelength of 1.06 micrometers . In addition, a smaller discharge pumped KrF excimer laser, based at the Clarendon Laboratory, University of Oxford, UK, has been built, giving approximately 2 J at a wavelength of 249 nm. A comparison of the x-ray emission from plasma generated by the two laser systems using various target materials has been made and evaluated with respect to their application to SXCM.