Broad angular multilayer analyzer for soft X-rays.

Using numerical optimization algorithm, non-periodic Mo/Si, Mo/Be, and Ni/C broad angular multilayer analyzers have been designed. At the wavelength of 13 nm and the angular range of 45~49 degrees , the Mo/Si and Mo/Be multilayer can provide the plateau s-reflectivity of 65% and 45%, respectively. At 5.7 nm, the s-reflectivity of Ni/C multilayer is 16% in the 44~46 degrees range. The non-periodic Mo/Si broad angular multilayer was also fabricated using DC magnetron sputtering, and characterized using the soft X-ray polarimeter at BESSY. The s-reflectivity is higher than 45.6% over the angular range of 45~49 degrees at 13 nm, where, the degree of polarization is more than 99.98%.

A focused ultrasoft x-ray microbeam for targeting cells individually with submicrometer accuracy.

The application of microbeams is providing new insights into the actions of radiation at the cell and tissue levels. So far, this has been achieved exclusively through the use of collimated charged particles. One alternative is to use ultrasoft X rays, focused by X-ray diffractive optics. We have developed a unique facility that uses 0.2-0.8-mm-diameter zone plates to focus ultrasoft X rays to a beam of less than 1 microm diameter. The zone plate images characteristic K-shell X rays of carbon or aluminum, generated by focusing a beam of 5-10 keV electrons onto the appropriate target. By reflecting the X rays off a grazing-incidence mirror, the contaminating bremsstrahlung radiation is reduced to 2%. The focused X rays are then aimed at selected subcellular targets using rapid automated cell-finding and alignment procedures; up to 3000 cells per hour can be irradiated individually using this arrangement.

Projected advances in laboratory soft x-ray systems and their applications.

Advances in x-ray laser plasma sources and zone plate optics since the early 1980s are reviewed. The improvements are projected into the early years of the 21st century and it is demonstrated that applications such as x-ray microscopy will become increasingly amenable to small scale laboratory systems.

Laser-generated plasmas: source requirements for x-ray microscopy.

Microscopic imaging using x rays has been made feasible by recent developments in techniques for manufacturing x-ray optical components and in synchrotron radiation sources. However, it is clear that x-ray microscopes cannot become widely available instruments if they have to rely on synchrotron radiation sources. Laser-generated plasmas can give intense bursts of x rays, and in this paper the requirements for two types of imaging, contact microradiography and scanning transmission x-ray microscopy, are discussed, with particular reference to the use of small commercially available lasers. Such lasers could be of use, particularly for scanning x-ray microscopes, but it is unlikely they will be capable of completely replacing synchrotrons as sources for x-ray microscopy.

X-ray microscopy and X-ray imaging.

Within a framework of an overview of the current status and potential of X-ray microscopy, a description is given of the development of the King's College scanning instrument which produced its first images in September, 1986. The instrument was mounted on the newly-built undulator beam line at the UK Science and Engineering Research Council's SRS synchrotron. There are consequently three sites worldwide where high-resolution X-ray microscopes with zone-plate optics are in operation. The other sites are BESSY-Berlin and NSLS-Brookhaven.