RESOLUTION IN SOFT-X-RAY MICROSCOPES

X-ray microscopes are able to image thick, wet biological specimens at 50 nm or better resolution, to perform elemental analysis at 0.1-10 mum resolution with as high as ppm sensitivity, and to analyze surface composition at 0.1-1 mum resolution. We concentrate here on the use of soft X-rays, where the wavelength is typically > 1 nm, although mention of some techniques and results at shorter wavelengths is also made. We discuss the physical principles behind X-ray microscopes, the types of optical systems used and their achievable resolution, resolution limitations imposed by radiation damage, and recent application of X-ray microscopes to the imaging of biological, materials science, geological, and other specimens.