Design and performance of a scanning ptychography microscope.

We have designed and constructed a dedicated instrument to perform ptychography measurements and characterization of multilayer Laue lenses nanofocusing optics. The design of the scanning microscope provides stability of components and minimal thermal drifts, requirements for nanometer scale spatial resolution measurements. We performed thorough laboratory characterization of the instrument in terms of resolution and thermal drifts with subsequent measurements at a synchrotron. We have successfully acquired and reconstructed ptychography data yielding 11 nm line focus.

An in-vacuum x-ray diffraction microscope for use in the 0.7-2.9 keV range.

A dedicated in-vacuum coherent x-ray diffraction microscope was installed at the 2-ID-B beamline of the Advanced Photon Source for use with 0.7-2.9 keV x-rays. The instrument can accommodate three common implementations of diffractive imaging; plane wave illumination; defocused-probe (Fresnel diffractive imaging) and scanning (ptychography) using either a pinhole, focused or defocused probe. The microscope design includes active feedback to limit motion of the optics with respect to the sample. Upper bounds on the relative optics-to-sample displacement have been measured to be 5.8 nm(v) and 4.4 nm(h) rms/h using capacitance micrometry and 27 nm/h using x-ray point projection imaging. The stability of the measurement platform and in-vacuum operation allows for long exposure times, high signal-to-noise and large dynamic range two-dimensional intensity measurements to be acquired. Finally, we illustrate the microscope's stability with a recent experimental result.

Differential phase contrast with a segmented detector in a scanning X-ray microprobe.

Scanning X-ray microprobes are unique tools for the nanoscale investigation of specimens from the life, environmental, materials and other fields of sciences. Typically they utilize absorption and fluorescence as contrast mechanisms. Phase contrast is a complementary technique that can provide strong contrast with reduced radiation dose for weakly absorbing structures in the multi-keV range. In this paper the development of a segmented charge-integrating silicon detector which provides simultaneous absorption and differential phase contrast is reported. The detector can be used together with a fluorescence detector for the simultaneous acquisition of transmission and fluorescence data. It can be used over a wide range of photon energies, photon rates and exposure times at third-generation synchrotron radiation sources, and is currently operating at two beamlines at the Advanced Photon Source. Images obtained at around 2 keV and 10 keV demonstrate the superiority of phase contrast over absorption for specimens composed of light elements.

Quantitative phase imaging with a scanning transmission x-ray microscope.

We obtain quantitative phase reconstructions from differential phase contrast images obtained with a scanning transmission x-ray microscope and 2.5 keV x rays. The theoretical basis of the technique is presented along with measurements and their interpretation.

X-ray imaging and microspectroscopy of plants and fungi.

X-ray fluorescence microscopy and microspectroscopy with micrometre spatial resolution and unprecedented capabilities for the study of biological and environmental samples are reported. These new capabilities are a result of both the combination of high-brilliance synchrotron radiation and high-performance X-ray microfocusing optics and the intrinsic advantages of X-rays for elemental mapping and chemical-state imaging. In this paper, these capabilities are illustrated by experimental results on hard X-ray phase-contrast imaging, X-ray fluorescence (XRF) imaging and microspectroscopy of mycorrhizal plant roots and fungi in their natural hydrated state. The XRF microprobe is demonstrated by the simultaneous mapping of the elemental distributions of P, S, K, Ca, Mn, Fe, Ni, Cu and Zn with a spatial resolution of approximately 1 x 3 micron and with an elemental sensitivity of approximately 500 p.p.b. Microspectroscopy with the same spatial resolution is demonstrated by recording near-edge X-ray absorption (XANES) spectra of Mn at a concentration of approximately 3 p.p.m.

Measurements of emittance and absolute spectral flux of the PETRA undulator at DESY Hamburg.

The first synchrotron radiation beamline using a 4 m-long undulator at the 12 GeV storage ring PETRA delivers hard X-ray photons usable up to 300 keV. The photon intensity is measured on an absolute scale in the energy range between 16 and 60 keV and compared with calculated intensities. The experimental set-up described is also used to measure the horizontal and vertical emittance of the source.