X-ray microscope

An alternative method of focusing X-rays is to use a tiny Fresnel zone plate of concentric gold or nickel rings on a silicon dioxide substrate.

[4] This microscope scanned samples using synchrotron radiation from a tiny pinhole and showed the abilities of both transmission and fluorescence microscopy.

Other developments in this period include the first holographic demonstration by Sadao Aoki and Seishi Kikuta in Japan,[5] the first TXMs using zone plates by Schmahl et al.,[6] and Stony Brook's experiments in STXM.

However, as new synchrotron-source-based microscopes were built in many groups, people realized that it was difficult to perform such experiments due to insufficient technological capabilities at that time, such as poor coherent illuminations, poor-quality x-ray optical elements, and user-unfriendly light sources.

With this increasing demand for X-ray microscopy in these fields, microscopes based on synchrotron, liquid-metal anode, and other laboratory light sources are being built around the world.

In July 2012, a group at DESY claimed a record spatial resolution of 10 nm, by using the hard X-ray scanning microscope at PETRA III.

Electron microscopy is widely used to obtain images with nanometer to sub-Angstrom level resolution but the relatively thick living cell cannot be observed as the sample has to be chemically fixed, dehydrated, embedded in resin, then sliced ultra thin.

However, it should be mentioned that cryo-electron microscopy allows the observation of biological specimens in their hydrated natural state, albeit embedded in water ice.

Until now, resolutions of 30 nanometer are possible using the Fresnel zone plate lens which forms the image using the soft x-rays emitted from a synchrotron.

Additionally, X-rays cause fluorescence in most materials, and these emissions can be analyzed to determine the chemical elements of an imaged object.

By analyzing the internal reflections of a diffraction pattern (usually with a computer program), the three-dimensional structure of a crystal can be determined down to the placement of individual atoms within its molecules.

[13] X-ray microscopy has its unique advantages in terms of nanoscale resolution and high penetration ability, both of which are needed in biological studies.

With the recent significant progress in instruments and focusing, the three classic forms of optics—diffractive,[14] reflective,[15][16] refractive[17] optics—have all successfully expanded into the X-ray range and have been used to investigate the structures and dynamics at cellular and sub-cellular scales.

In 2005, Shapiro et al. reported cellular imaging of yeasts at a 30 nm resolution using coherent soft X-ray diffraction microscopy.