APS high heat load monochromator

Lee, W.K.; Mills, D.

doi:10.2172/10132009

Cited by 3 publications

(5 citation statements)

References 1 publication

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“…V.3), the planes of diffraction make an angle β with the crystal surface, thereby spreading the power density on the crystal surface by a factor of 1/(sinθ cosβ), where θ is Bragg's angle. In the APS design [6], the inclination angle and energy range were originally chosen so that the power density on the crystal surface does not exceed about 5 W/mm 2 and the crystal is under 250 mm long [6]. The surface power density limit was chosen based on previous experimental and computer simulation results.…”

Section: Crystal Geometry and Cooling Parametersmentioning

confidence: 99%

“…The APS has put considerable effort into exploring various approaches to mitigate the thermal distortion problem in x-ray optical components. In particular, for double-crystal monochromators, the use of silicon cooled with liquid gallium [1][2][3], silicon at cryogenic temperatures [4][5], the effect of crystal geometry (inclined [6][7][8][9][10][11][12], asymmetric [13], and thin crystals), and the use of diamond [14][15] instead of silicon are all being studied both experimentally and computationally. This document summarized a series of finite element analyses (FEA) performed on room temperature silicon for the three standard APS source, namely, a bending magnet, wiggler A, and undulator A.…”

Section: Introductionmentioning

confidence: 99%

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A finite element analysis of room-temperature silicon crystals for the advanced photon source bending-magnet and insertion-device beamsa)

Assoufid

Lee

Mills

1995

Review of Scientific Instruments

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The third generation of synchrotron radiation sources, such as the Advanced Photon Source (APS), will provide users with a high brilliance x-ray beam with high power and power densities. In many cases, the first optical component to intercept the x-ray beam is a silicon-crystal monochromator. Due to extreme heat loading, the photon throughput and brilliance will be severely degraded if the monochromator is not properly designed (or cooled). This document describes a series of finite element analyses performed on room temperature silicon for the three standard APS sources, namely, the bending magnet, wiggler A, and undulator A. The modeling is performed with the silicon cooled directly with water or liquid gallium through rectangular channels. The temperature distributions and thermally induced deformations are presented.

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Section: Crystal Geometry and Cooling Parametersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A finite element analysis of room-temperature silicon crystals for the advanced photon source bending-magnet and insertion-device beamsa)

Assoufid

Lee

Mills

1995

Review of Scientific Instruments

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“…The second, short crystal may be translated in direction of the beam to fulfill the geometric boundary conditions at low angles and high energies. The use of a short second crystal on a translation stage instead of a long one as originally proposed by [1,2] makes it easier to ensure perfect crystal properties. During energy scans, only the Bragg angle and the translation responsible for the fixed-exit condition are moved.…”

Section: Monochromator Designmentioning

confidence: 99%

“…For that purpose a new compact double-crystal monochromator was designed which should provide a fixed-exit beam over a wide energy range suitable for step-by-step energy scans for conventional XAFS and continuous energy scans for QEXAFS measurements. The optical design is based on ideas proposed by Mills, King and Lee [1,2].…”

Section: Introductionmentioning

confidence: 99%

New XAFS Facility for In-Situ Measurements at Beamline C at HASYLAB

Rickers

Drube

Schulte‐Schrepping

et al. 2007

AIP Conference Proceedings

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A XAFS-experiment allowing for in-situ experiments has been set up at DORIS bending magnet beamline C. For that purpose, a new double-crystal, UHV-compatible monochromator with fast scanning capability was designed. This fixed-exit monochromator uses two crystal sets on a common central rotation axis driven by an ex-vacuo goniometer. Bragg angles range from 5° to 55.5° resulting in a total energy range 2.3 -43.4 keV using Si(111)/(311) crystal sets. Crystal pairs can be remotely selected by translating the vacuum chamber. Energy encoding is performed using an optical encoder system. The standard XAFS sample environment is set-up in vacuo and can be adapted for special sample environments. For in-situ experiments, the beamline is equipped with twelve gas lines. An exhaust line allows toxic/reactive gases to be handled. As an initial performance test of the instrument, Ti, Cr, Fe and Cu XAFS and Ce K-shell QEXAFS measurements were performed.

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“…The crystal drive/vacuum part of the monochromator system used in these tests was built by Kohzu-Seiki, Japan, and will hence be referred t o as the Kohzu monochromator. Details can be found in reference [4]. It essentially consists of an in-vacuum rotation stage driven by a DC servo motor that sits outside the vacuum chamber.…”

Section: Design Featuresmentioning

confidence: 99%

Identification of root cause of vibration of a liquid-gallium-cooled silicon monochromator and recommendations for abatement

Chen¹,

Zhu²,

Wambsganss³

et al. 1994

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This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof. nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, ream-' mendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Govemment or anyagency thereof. Work supported by U. S. DEPARTMENT OF ENERGY Office of Basic Energy Sciences DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document.

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APS high heat load monochromator

Cited by 3 publications

References 1 publication

A finite element analysis of room-temperature silicon crystals for the advanced photon source bending-magnet and insertion-device beamsa)

A finite element analysis of room-temperature silicon crystals for the advanced photon source bending-magnet and insertion-device beamsa)

New XAFS Facility for In-Situ Measurements at Beamline C at HASYLAB

Identification of root cause of vibration of a liquid-gallium-cooled silicon monochromator and recommendations for abatement

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