Images of magnetic structures in a SmCo/Fe bilayer have been obtained using a circularly polarized hard x-ray microprobe. This probe combines circularly polarizing and microfocusing optics (either Fresnel zone plate or Kirkpatrick-Baez mirrors) to provide a highly polarized, small cross-section x-ray beam in the energy range between 5 and 12 keV. By using x-rays in this energy range, we can penetrate the top layers of the sample and therefore are able to measure the magnetic domains of buried magnetic structures with a resolution of ~5 micrometers . Contrast between magnetic domains is obtained by measuring the x-ray magnetic circular dichroism signal for different points as the beam is scanned across the sample. Images of the magnetic domain structure in a 1600-A-thick buried SmCo layer of a SmCo/Fe bilayer were taken as a function of the externally applied magnetic field. These images show the nucleation of large domains ( > 100 micrometers ) whose domain walls are oriented perpendicular to the applied field direction. Upon increasing the applied field, the images show the growth of the local reversed domains as the domain walls propagate across the sample, leading to a complete reorientation of the hard magnetic layer.

Cellular micro-irradiation is now seen as a potent method for understanding how radiations interact with living cells and tissues. The strength of this technique lies in its ability to deliver precise doses of radiation to selected individual cells in vitro, or to pre-selected targets within cells. We have recently developed a focused soft X-ray microprobe for targeting individual cells. The use of focused X-rays for this type of study is unique, and is being applied in a number of novel experiments. One important application is to study the so-called bystander effect where un-irradiated cells are seen to respond to signals from nearby irradiated cells. It is also being used as a sub-cellular probe to compare the effects of nuclear versus cytoplasmic targeting. Our facility uses a 0.4-0.8 mm diameter zone plate to focus soft X-rays to a sub-micron beam. This is then aimed at selected sub-cellular targets using rapid automated cell finding and alignment procedures. The zone plate images characteristic-K X-rays of carbon or aluminium, generated by focusing a beam of 5-10 keV electrons on to the appropriate target. The current arrangement will deliver about 10000 photons/sec to the focus (sufficient to irradiate several tens of cells per minute).

The x-ray microdiffraction technique was used to study lattice-strain field and phase concentration near the surface of a carburised steel blade on a micron-length scale. Our results show larger compressive lattice strains and more completed phase transformation at the location near the tip of the blade than that the locations away from the tip.

X-ray nanotomography has developed into a powerful new tool for three-dimensional structural analysis. The scanning approach offers capabilities that are competitive with full- field imaging. Current and ultimate limitations of nanotomography are examined in light of recent work.

An x-ray imaging microscopy experiment was performed at the x-ray energy of 8 keV. A Fresnel zone plate (FZP) fabricated by electron-beam lithography technique was used as an objective. Material of the zone structure is tantalum. The experiment was done at the undulator beamline BL47XU of Spring-8. Undulator radiation was monochromatized by passing through a liquid nitrogen cooled Si 111 double crystal monochromator. In order to eliminate speckle-like background noise, a partial coherent illumination was introduced by using a beam diffuser consisted of graphite powder. Beam spread of the illumination with the diffuser was about 35 (mu) rad. A charge coupled device (CCD) camera coupled with a phosphor screen and a microscope objective (x 12 or x 24) was used as an image detector. Converted pixel size with the x 24 lens was 0.5micrometers . Magnification of the x-ray microscope system was set to be 7.61-13. Pitch of 0.6micrometers (0.3 micrometers line and 0.3micrometers space) pattern of the test chart was resolved, and the outermost zone structure of the same type of FZP was observed. Imaging properties are also discussed by using Hopkins optical imaging theory.

Modern technology permits the fabrication of Kirkpatrick-Baez (KB) multilayer optics with performance close to the theoretical limit. We have constructed a KB field-imaging microscope which operates in the x-ray energy range 6-10 keV with a field of view of 40-150 micrometers . The optics perform at a reflectivity of 80% at the first Bragg peak. Using highly-collimated synchrotron radiation, we realize a resolution of 900 nm at 9 keV. The intensity and magnification are sufficient to perform real-time imaging with a CCD x-ray camera, with increases in field of view and resolution at this energy due to improvements in both data collection and image processing. The collimation of the incident radiation corresponds to Koehler illumination. The dynamic range of the images using a 12-bit camera allows us to extend the field of view at the Bragg reflection over several Kiessig fringes. We have adjusted the energy to take advantage of absorption at the excitation edges of elements and have performed imaging using circularly polarized radiation. We have used this instrument to demonstrate wide-field imaging in both absorption and diffraction. We present magnified images of multiple layers in a test integrated circuit in absorption and of a metal single crystal in diffraction.

A new spectrometer based on plane crystal wavelength dispersive method using a position sensitive proportional counter (PSPC) in conjunction with x-ray microbeam formed by monolithic polycapillary x-ray focusing lens has been developed. The new spectrometer could be used for XRMF analysis with high sensitivity, high spatial resolution and energy resolution simultaneously. The minimum spot sizes of the Cu-K(alpha) focused by the lens was 50micrometers . The energy resolution of 5.8 eV was obtained for Ti-K(alpha) by means of the spectrometer.

Parabolic compound refractive lenses (PCRLs) are high quality hard x-ray imaging optics that can be used to image a synchrotron source onto a sample in a strongly demagnifying setup. This allows to produce an intensive microbeam with lateral extensions in the (sub-)micrometer range. Aluminium PCRLs can be operated in an energy range from about 10keV to 60keV and withstand the high heat load of the white beam of an ESRF undulator source. The microbeam properties using monochromatic and single undulator harmonic (pink) radiation are discussed, focusing on beam size, depth of field, background, flux, and gain. The large depth of focus allows to scan fairly large samples (a few millimeters in thickness) with a beam of constant lateral extension. This makes tomographic scanning techniques, such as fluorescence microtomography possible. As applications, fluorescence microtomography of plant samples with sub-cellular resolution and the mapping of trace elements in single cancer cells is shown.

The planar microelectronics technology, involving lithography and highly anisotropic plasma etching techniques, allows manufacturing high quality refractive and diffractive lenses, which may be used in hard X-ray microprobe and microscopy applications. These silicon lenses are mechanically robust and can withstand high beat load of the white X-ray beam at third generation synchrotron radiation sources. For the first time we designed and manufactured a new type of lenses: kinoform lenses and parabolic lenses with scaled reduction of curvature radii. The theoretical background for such type of lens features is presented. Focusing properties in the terms of focus spot and efficiency of all these lenses were tested at the ESRF beamlines. Magnified imaging with planar lense was realized. Some future developments are discussed.

X-ray microbeam using Fresnel zone plate as a beam focusing device has been tested at an undulator beamline of Spring-8. The zone material is tantalum with thickness of 1 micrometers , and the zone structure is fabricated by using electron beam lithography technique. The outermost zone width of the zone plate is 0.25micrometers . By utilizing a fully coherent illumination, a focused spot size near to the diffraction- limit (0.3micrometers ) has been achieved at an X-ray energy of 8 keV. The measured beam profiles shows good agreement with the theoretical profile. The measured diffraction efficiency agrees well with theoretical value within an X- ray energy region from 6 keV to 10 keV. A scanning microscopy experiment has also been performed in order to evaluate the spatial resolution. Fine structures of up to 0.2micrometers are clearly observed in the measured image. The modulation transfer function derived from the measured image is 10% at 0.2micrometers line and 0.2micrometers space.

Diffractive optics for the x-ray range have to meet the various requirements of experimental set-ups at synchrotron or other light sources. In the case of focusing elements it is essential that the devices are matched to parameters such as the photon energy and spatial coherence of the source, as well as the required spatial resolution, working distance, and diffraction efficiency. In some cases, a suppression of disturbing diffraction orders requires additional features such as an opaque central stop integrated into the lens. The Laboratory for Micro- and Nanotechnology provides the essential technologies necessary for the design and fabrication of diffractive x-ray lenses for a wide range of photon energies and applications. Over the past years, a large variety of optics tailored to the specific needs of x-ray optical experiments have been fabricated and tested. These include transmission Fresnel phase zone plate for microscopy, microprobe, or beam monitoring applications, as well as condensers to increase the flux in waveguiding experiments in the hard x-ray range. An overview of the nanofabrication technologies and a selection of experiments demonstrating the devices performance are presented.

We describe the fabrication and testing of a novel type of tunable transmission hard x-ray optics. The diffractive elements are generated by electron beam lithography and chemical wet etching of <110> oriented silicon substrates. Structures with widths down to 100 nm and extreme aspect ratios were obtained using this method. By tilting the lenses with respect to the x-ray beam, the effective path through the phase shifting structures can be varied. This makes it possible to optimize the diffraction efficiency for a wide range of photon energies, and to obtain effective aspect ratios not accessible with untilted optics. The diffraction efficiency of a Fresnel lens was measured for various energies between 8 keV and 29 keV. Values close to the theoretical limit (approx. 35%) were obtained. The described technique provides focusing in one direction only. For two-dimensional focusing, two linear lenses with different focal lengths and orthogonal orientations can be placed along the optical axis. Depending on the coherence properties of the source, such an arrangement can improve the resolution and flux compared to a single circular zone plate. The wet etching technique is also applied to the fabrication of linear gratings with pseudo-random pitch, which will be used as one-dimensional decoherers to adapt the coherence of a synchrotron beam in a defined way. Linear gratings with uniform line density can be used as beam splitters for applications such as holography or interferometry.

We describe Kirkpatrick-Baez (KB) reflecting mirror systems that have been developed at the European Synchrotron Radiation Facility (ESRF). They are intended to be used mainly in the hard x-ray domain from 10 KeV to 30 KeV for microfluorescence, microdiffraction and projection microscopy applications. At 19 KeV a full width at half maximum (FWHM) spot size of 200x600 nanometers has been measured and with an estimated irradiance gain of 3.5x10⁵. The alignment and bending processes of the system are automated based on the wavefront information obtained by sequentially scanning slits and reading a position-sensitive device located in the focal plane. The sub-microradian sensitivity of this method allows us to predict the spot size and ot provide a metrology map of the surfaces for future improvements of the performances. A novel device based on specular reflection by a micromachined platinum mirror has been used to determine the spot size with an equivalent slit size of less than 100 nanometers. Projection phase images of submicron structures are presented which clearly show both the high potential and also the present limitations of the system. First microfluorescence images obtained at 20.6 KeV are shown. Finally, a roadmap towards diffraction-limited performance with metal and multilayer surfaces is presented.

An integrating solid state detector with segmentation has been developed that addresses the needs in scanning transmission x-ray microscopy below 1 keV photon energy. The detector is not cooled and can be operated without an entrance window which leads to a total photon detection efficiency close to 100%. The chosen segmentation with 8 independent segments is matched to the geometry of the STXM to maximize image mode flexibility. In the bright field configuration for 1 ms integration time and 520 eV x-rays the rms noise is 8 photons per integration.

Point spread functions (PSF) of some kinds of x-ray imaging detectors are directly measured using x-ray microbeam. The experiment has been performed at bending magnet beamline BL20B2 and undulator beamline BL2oXU of Spring-9. The microbeam is focused using a Fresnel zone plate (FZP) with coherent illumination to 0.3micrometers (almost outermost zone width of the FZP). The imaging detectors are put at the focal plane and directly detect the microbeam. Two types of high spatial resolving detectors are tested. One is x-ray- electron conversion type with electro-magnetic lens, and spatial resolution is estimated to 0.7micrometers . The other is x-ray-visible light conversion type with optical lens and the spatial resolution is estimated to 1.0micrometers .

The soft x-ray, full-field microscope XM-1 at Lawrence Berkeley National Laboratory's (LBNL) Advanced Light Source has already demonstrated its capability to resolve 25-nm features. The soft x-ray, full-field microscope XM-1 at Lawrence Berkeley National Laboratory's (LBNL) Advanced Light Source has already demonstrated its capability to resolve 25-nm features. This was accomplished using a micro zone plate (MZP) with an outer zone width of 25 nm. Limited by the aspect ratio of the resist used in the fabrication, the gold-plating thickness of that zone plate is around 40 nm. However, some applications, in particular, biological imaging, prefer improved efficiency, which can be achieved by high-aspect-ratio zone plates. We accomplish this by using a bilayer-resist process in the zone plate fabrication. As our first attempt, a 40-nm-outer-zone-width MZP with a nickel-plating thickness of 150 nm (aspect ratio of 4:1) was successfully fabricated. Relative to the 25-nm MZP, this zone plate is ten times more efficient. Using this high-efficiency MZP, a line test pattern with half period of 30 nm is resolved by the microscope at photon energy of 500 eV. Furthermore, with a new multilayer mirror, the XM-1 can now perform imaging up to 1.8 keV. An image of a line test pattern with half period of 40 nm has a measured modulation of 90%. The image was taken at 1.77 keV with the high-efficiency MZP with an outer zone width of 35 nm and a nickel-plating thickness of 180 nm (aspect ratio of 5:1). XM-1 provides a gateway to high-resolution imaging at high energy. To measure frequency response of the XM-1, a partially annealed gold island pattern was chosen as a test object. After comparison with the SEM image of the pattern, the microscope has the measured cutoff of 19 nm, close to the theoretical one of 17 nm. The normalized frequency response, which is the ratio of the power density of the soft x-ray image to that of the SEM image, is shown in this paper.