J. Barraza

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.

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.

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.

The advanced photon source X-ray transmitting beam-position-monitor tests at the national synchrotron light source X-25 beamline

Abstract A synthetic-diamond-based X-ray transmitting beam-position monitor has been studied using focused white beam at the National Synchrotron Light Source X-25 wiggler beamline. Of particular interest are the possibilities to design an integral window and filter/photon beam-position monitor for the Advanced Photon Source high-heat-flux insertion-device beamlines. The preliminary measurements were taken using two synthetic-diamond blade samples with different thicknesses and cooling configurations. The monitor (consisting of a vacuum vessel, an ion pump, a water-cooling base, a blade mounting block, and electric feedthroughs) was mounted on a three-dimensional ( x , y , φ ) stepping-motor-driven stage with a 0.064-μm stepping size and a 0.1-μm linear encoder resolution. An infrared camera system was used to monitor and record the diamond blade surface temperature field through a sapphire window and test results are presented.

CVD-diamond-based position sensitive photoconductive detector for high-flux X-rays and gamma rays

A position-sensitive photoconductive detector (PSPCD) using insulating-type CVD diamond as its substrate material has been developed at the Advanced Photon Source (APS). Several different configurations, including a quadrant pattern for a X-ray-transmitting beam position monitor (TBPM) and 1-D and 2-D arrays for PSPCD beam profilers, have been developed. Tests on different PSPCD devices with high-heat-flux undulator white X-ray beam, as well as with gamma-ray beams from /sup 60/Co sources have been done at the APS and National Institute of Standards and Technology (NIST). It was proven that the insulating-type CVD diamond can be used to make a hard X-ray and gamma-ray position-sensitive detector that acts as a solid-state ion chamber. These detectors are based on the photoconductivity principle. A total of eleven of these TBPMs have been installed on the APS front ends for commissioning use. The linear array PSPCD beam profiler has been routinely used for direct measurements of the undulator white beam profile. More tests with hard x-rays and gamma rays are planned for the CVD-diamond 2-D imaging PSPCD. Potential applications include a high-dose-rate beam profiler for fourth-generation synchrotron radiation facilities, such as free-electron lasers.

Support systems for optics in the experiment stations at the Advanced Photon Source

Support systems have been designed for optics in the experiment stations of the Advanced Photon Source at Argonne National Laboratory. These systems utilize modular precision positioning slides and stages arranged in 3‐point kinematic mount fashion for optimum mechanical stability. Through the use of novel configurations, these systems can achieve large linear motions, six degree‐of‐freedom motion, and large load capacities without sacrificing valuable experimental station space. This paper will discuss the designs and specifications of the positioning systems developed.

Vibratory response modeling and verification of a high-precision optical positioning system

A generic vibratory-response modeling program has been developed as a tool for designing high-precision optical positioning systems. Based on multibody dynamics theory, the system is modeled as rigid-body structures connected by linear elastic elements, such as complex actuators and bearings. The full dynamic properties of each element are determined experimentally or theoretically, then integrated into the program as inertial and stiffness matrices. Utilizing this program, the theoretical and experimental verification of the vibratory behavior of a double- multiplier monochromator support and positioning system is presented. Results of parametric design studies that investigate the influence of support floor dynamics and highlight important design issues are also presented. Overall, good matches between theory and experiment demonstrate the effectiveness of the program as a dynamic modeling tool.

Progress of the APS high heat load x-ray beam position monitor development

Several novel design developments have been established for the Advanced Photon Source (APS) insertion device (ID) X-ray beam position monitor (XBPM) to improve its performance: --- optimized geometric configuration of the monitor’s sensory blades; --- smart XBPM system with an intelligent digital signal processor, which provides a self-learning and calibration function; and --- Transmitting XBPM with prefiltering in the commissioning windows for the front end. In this write-up, we summarize the recent progress on the XBPM development for the APS ID front ends.

Beamline standard component designs for the Advanced Photon Source

The Advanced Photon Source (APS) has initiated a design standardization and modularization activity for the APS synchrotron radiation beamline components. These standard components are included in components library, subcomponents library, and experimental station library. This paper briefly describes these standard components using both technical specifications and sideview drawings.