T. Oversluizen

Liquid gallium cooling of silicon crystals in high intensity photon beams (invited)

The high‐brilliance, insertion‐device‐based photon beams of the next generation of synchrotron sources (Argonne’s APS and Grenoble’s ESRF) will deliver large thermal loads (1–10 kW) to the first optical elements. Considering the problems that present synchrotron users are experiencing with beams from recently installed insertion devices, new and improved methods of cooling these first optical elements, particularly when they are diffraction crystals, are clearly needed. A series of finite element calculations were performed to test the efficiency of new cooling geometries and various cooling fluids. The best results were obtained with liquid Ga metal flowing in channels just below the surface of the crystal. Ga was selected because of its good thermal conductivity and thermal capacity, low melting point, high boiling point, low kinetic viscosity, and very low vapor pressure. Its very low vapor pressure, even at elevated temperatures, makes it especially attractive in UHV conditions. A series of experiment...

Performance of a directly water‐cooled silicon crystal for use in high‐power synchrotron radiation applications

Results of measurements made using the multipole wiggler at beamline 16 of Photon Factory are reported. Double crystal rocking curves, Si(111) and Si(333) topographs, and thermal maps of the cooled‐crystal surface were measured at total incident power levels up to 1600 W and power densities up to 0.7 W/mm2, for two different crystal designs. Significant crystal deformation occurred in the form of surface curvature for both designs. Finite element calculations provided a preview of the experimental results and proved very valuable in interpretation of the measurements.

Compact high flux photon beam position monitor

We have developed a new compact water‐cooled beam position monitor for use at the NSLS X‐13 Insertion Device Development beamline, currently fitted with a high‐power, high‐brightness soft‐x‐ray undulator. We describe the novel geometry of the monitor and present the results of tests which explore its sensitivity, stability, and linearity. These results were obtained on the NSLS Beamline Research and Development white light beamline, U14B, on the VUV ring and suggest that beam position monitors of this type might be adapted to other facilities with similar spectral characteristics.

Optical design and performance of the inelastic scattering beamline at the National Synchrotron Light Source

Phase I of the X21 beamline at the National Synchrotron Light Source was commissioned during 1993. The research program at the X21 beamline is focused on the study of electronic excitations in condensed matter with total energy resolution of 0.1–1.0 eV. The source is a 27‐pole hybrid wiggler. A water‐cooled horizontal focusing Si(220) monochromator and a spherically bent Si(444) analyzer were installed and commissioned. At 8 keV the energy resolution of the monochromator is about 0.7 eV, and the energy resolution of the analyzer is about 0.1 eV. Results from several selected experiments are also discussed.

Optical design and performance of the X25 hybrid wiggler beam line at the National Synchrotron Light Source

The X25 beam line at the National Synchrotron Light Source (NSLS) began full‐power commissioning in 1990. It extracts radiation from a 27 pole hybrid wiggler, which produces up to 1.8 kW of total power with a peak horizontal density of 450 W/mrad and critical energy of 4.6 keV. The design and performance of the beam line optics are described, in particular, the cooling of the first monochromator crystal.

Kinematic mounting systems for National Synchrotron Light Source beamlines and experiments

Methods for kinematically mounting equipment are well established, but applications at synchrotron radiation facilities are subject to constraints not always encountered in more traditional laboratory settings. Independent position adjustment of beamline components can have significant benefits in terms of minimizing time spent aligning, and maximizing time spent acquiring data. In this article, we use examples taken from beamlines at the National Synchrotron Light Source to demonstrate approaches for optimization of the reproducibility, stability, excursion, and set‐up time for various situations. From our experience, we extract general principles which we hope will be useful for workers at other synchrotron radiation facilities.

A high‐energy double‐crystal fixed exit monochromator for the X17 superconducting wiggler beam line at the NSLS

A high‐energy double‐crystal x‐ray monochromator has been constructed for use on the X‐17 beam line at the National Synchrotron Light Source (NSLS). Its design is based on the ‘‘boomerang’’ right angle linkage, and features a fixed exit beam, a cooled first crystal, and an energy range of 8–92 keV. The entire mechanism is UHV compatible. The design is described and performance details, obtained in testing at the X17 beam line, are presented.

UHV photoelectron X-ray beam position monitor☆

Abstract As part of our research program to develop viable beam position monitors for both the X-ray and the VUV beamlines at the NSLS, we have constructed vertical photon beam position monitors which are presently mounted in two front-end tanks in the X-ray ring. These area-type detectors are located before the safety shutters and are, therefore, able to monitor the beam position even during injection. The features of this type of monitor which contribute to its long-term stability, position sensitivity, and immunity to horizontal beam motion have been examined and are discussed.

UHV piezoelectric translator

Abstract A UHV compatible piezoelectric translator has been developed to correct for angular misalignments in the crystals of a UHV X-ray monochromator. The unit is small, bakeable to 150°C, and use only ceramic materials for insulation. We report on the construction details, vacuum compatibility, mechanical properties, and uses of the device.

X13A: A versatile soft x‐ray undulator beamline

The undulator based beamline X13A at the National Synchrotron Light Source has been commissioned recently. The X13 undulator has an 8 cm period, and its first harmonic is in the energy range of 200–700 eV at the nominal ring energy of 2.5 GeV. The beamline uses horizontally deflecting optics. It consists of a SiC plane mirror, a water cooled entrance slit, a spherical grating, and two fixed exit slits. A flux of more than 1012 photons/s at 450 eV has been measured at X13A with an aluminum‐oxide photodiode with a 200 μm entrance slit, a 500 μm exit slit, and a ring current of 242 mA. A VF3 absorption spectrum recorded at X13A shows the monochromator resolving power is at least 1000 at ∼500 eV with 30 μm entrance and exit slits, in agreement with calculations. The X13A beamline will be used for x‐ray coherence studies, spectroscopy, and multilayer reflectivity measurements as well as for x‐ray instrumentation diagnostics.