D. Shu

A unique polarized x-ray facility at the advanced photon source

To use the unique element-specific nature of polarized x-ray techniques to study a wide variety of problems related to magnetic materials, we have developed a dual-branch sector that simultaneously provides both hard and soft x-ray capabilities. This facility, which is located in sector 4, is equipped with two different insertion devices providing photons in both the intermediate (0.5–3 keV) and hard x-ray regions (3–100 keV). This facility is designed to allow the simultaneous branching of two undulator beams generated in the same straight section of the ring.

A beamline for 1–4 keV microscopy and coherence experiments at the Advanced Photon Source

The third‐generation Advanced Photon Source will open up dramatic new opportunities for experiments requiring coherent x‐rays, such as scanning x‐ray microscopy, interferometry, and coherent scattering. We are building a beamline at the Advanced Photon Source to exploit the potential of coherent x‐ray applications in the 1–4 keV energy region. A high brightness 5.5‐cm‐period undulator supplies the coherent x‐rays. The beamline uses horizontally deflecting grazing‐incidence optical elements to preserve the coherence of the undulator beam. The optics have multilayer coatings for operation at energies above 1.5 keV. This paper discusses the beamline design and its expected performance.

An inelastic X-ray spectrometer with 2.2 meV energy resolution

We present a new spectrometer at the Advanced Photon Source for inelastic X-ray scattering with an energy resolution of 2.2 meV at an incident energy of 21.6 keV. For monochromatization, a nested structure of one silicon channel cut and one ‘artificial’ channel cut is used in forward-scattering geometry. The energy analysis is achieved by a two-dimensional focusing silicon analyzer in backscattering geometry. In the first demonstration experiments, elastic scattering from a Plexiglas TM sample and two dispersion curves in a beryllium single crystal were measured. Based on these data sets, the performance of the new spectrometer is discussed. Published by Elsevier Science B.V.

Performance of a double-multilayer monochromator at Beamline 2-BM at the Advanced Photon Source

We describe the performance of the double-multilayer monochromator that is installed at bending magnet beamline 2-BM at the Advanced Photon Source. In order to achieve continuous operation over energies from 3.2 to 10.9 keV, four different multilayer stripes were deposited onto Si substrates using the in-house sputtering deposition facility at the APS. The optical performance of the four stripes depends on their operating energy ranges, and produces 45%–75% peak reflectivity at first-order reflection with a 1%–6% bandwidth and a total flux increase of 20–40 compared to the Si(111) double-crystal monochromator.

The APS X-ray undulator photon beam position monitor and tests at CHESS and NSLS

Abstract The advent of third generation synchrotron radiation sources, like the Advanced Photon Source (APS), will provide significant increases in brilliance over existing synchrotron sources. The APS X-ray undulators will increase the brilliance in the 3–40 keV range by several orders of magnitude. Thus, the design of the photon beam position monitor is a challenging engineering task. The beam position monitors must withstand the high thermal load, be able to achieve submicron spatial resolution while maintaining their stability, and be compatible with both undulators and wigglers. A preliminary APS prototype photon beam position monitor consisting of a CVD-diamond-based, tungsten-coated blade was tested on the APS/CHESS undulator at the Cornell High Energy Synchrotron Radiation Source (CHESS) and on the NSLS X-13 undulator beamline. Results from these tests, as well as the design of this prototype APS photon beam position monitor, will be discussed in this paper.

Optomechanical Design of a Hard X-ray Nanoprobe Instrument with Nanometer-Scale Active Vibration Control

We are developing a new hard x‐ray nanoprobe instrument that is one of the centerpieces of the characterization facilities of the Center for Nanoscale Materials being constructed at Argonne National Laboratory. This new probe will cover an energy range of 3–30 keV with 30‐nm spacial resolution. The system is designed to accommodate x‐ray optics with a resolution limit of 10 nm, therefore, it requires staging of x‐ray optics and specimens with a mechanical repeatability of better than 5 nm. Fast feedback for differential vibration control between the zone‐plate x‐ray optics and the sample holder has been implemented in the design using a digital‐signal‐processor‐based real‐time closed‐loop feedback technique. A specially designed, custom‐built laser Doppler displacement meter system provides two‐dimensional differential displacement measurements with subnanometer resolution between the zone‐plate x‐ray optics and the sample holder. The optomechanical design of the instrument positioning stage system with n...

A cryogenically stabilized meV-monochromator for hard X-rays.

The design and performance results for a cryogenically stabilized high-resolution monochromator for 23.880 keV (lambda = 52 pm) X-rays are presented. The four-crystal-reflection monochromator is suitable for nuclear resonant scattering measurements from 119Sn compounds using synchrotron radiation. The design includes a low-vibration cryostat that maintains two of the four crystal reflections at a temperature where the coefficient for thermal expansion of the crystalline material (silicon) vanishes. Test results demonstrate a 1.3 meV bandwidth with negligible broadening due to vibrations and a spectral efficiency of 37% when used with an undulator source.

Design and performance of an X-ray scanning microscope at the Hard X-ray Nanoprobe beamline of NSLS-II

A hard X-ray scanning microscope installed at the Hard X-ray Nanoprobe beamline of the National Synchrotron Light Source II has been designed, constructed and commissioned. The microscope relies on a compact, high stiffness, low heat dissipation approach and utilizes two types of nanofocusing optics. It is capable of imaging with ∼15u2005nm × 15u2005nm spatial resolution using multilayer Laue lenses and 25u2005nm × 26u2005nm resolution using zone plates. Fluorescence, diffraction, absorption, differential phase contrast, ptychography and tomography are available as experimental techniques. The microscope is also equipped with a temperature regulation system which allows the temperature of a sample to be varied in the range between 90u2005K and 1000u2005K. The constructed instrument is open for general users and offers its capabilities to the material science, battery research and bioscience communities.

Design of a dedicated beamline for x‐ray microfocusing‐ and coherence‐based techniques at the Advanced Photon Source

A dedicated insertion‐device beamline has been designed and is being constructed at the Advanced Photon Source (APS) for development of x‐ray microfocusing‐ and coherence‐based techniques and applications. Important parameters considered in this design include preservation of source brilliance and coherence, selectable transverse coherence length and energy bandwidth, high beam angular stability, high order harmonic suppression, quick x‐ray energy scan, and accurate and stable x‐ray energy. The overall design of this beamline layout and the major beamline components are described. The use of a horizontally deflecting mirror as the first optical component is one of the main features of this beamline design, and the resulting advantages are briefly discussed.

Precision white-beam slit design for high power density x-ray undulator beamlines at the Advanced Photon Source

A set of precision horizontal and vertical white‐beam slits has been designed for the Advanced Photon Source x‐ray undulator beamlines at Argonne National Laboratory. There are several new design concepts applied in this slit set, including a grazing‐incidence knife‐edge configuration to minimize the scattering of x rays downstream, enhanced heat transfer tubing to provide water cooling, and a secondary slit to eliminate the thermal distortion on the slit knife edge. The novel aspect of this design is the use of two L‐shaped knife‐edge assemblies, which are manipulated by two precision X‐Z stepping linear actuators. The principal and structural details of the design for this slit set are presented in this paper.