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Title: Stress mitigation of x-ray beamline monochromators using topography test unit.

Abstract

Silicon and diamond monochromators (crystals), often used in the Advanced Photon Source X-ray beamlines, require a good quality surface finish and stress-free installation to ensure optimal performance. The device used to mount the crystal has been shown to be ajor contributing source of stress. In this case, an adjustable mounting device is an effective method of reducing stresses and improve the rocking curve to levels much closer to ideal. Analysis by a topography test unit has been used to determine the distribution of stresses and to measure the rocking curve, as well as create CCD images of the crystal. This paper describes the process of measuring these stresses and manipulating the mounting device and crystal to create a substantially improved monochromator.

Authors:
; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
OSTI Identifier:
982024
Report Number(s):
ANL/XSD/JA-57247
Journal ID: 1097-0002; TRN: US1004258
DOE Contract Number:
DE-AC02-06CH11357
Resource Type:
Conference
Resource Relation:
Journal Name: Adv. X-ray Anal.; Journal Volume: 50; Journal Issue: 2007; Conference: 2006 Denver X-Ray Conference; Aug. 7, 2006 - Aug. 11, 2006; Denver, CO
Country of Publication:
United States
Language:
ENGLISH
Subject:
43 PARTICLE ACCELERATORS; ADVANCED PHOTON SOURCE; CHARGE-COUPLED DEVICES; CRYSTALS; DIAMONDS; DISTRIBUTION; EQUIPMENT; IMAGES; INSTALLATION; LEVELS; MEETINGS; MITIGATION; MONOCHROMATORS; NEUTRON DIFFRACTION; PERFORMANCE; SILICON; STRESSES; SURFACES; TOPOGRAPHY; UNITS; WELLS

Citation Formats

Maj, J., Waldschmidt, G., Baldo, P., Macrander, A., Koshelev, I., Huang, R., Maj, L., Maj, A., Univ. of Chicago, Northeastern Ohio Univ. Coll. of Medicine, and Rosalind Franklin Univ. of Medicine and Science. Stress mitigation of x-ray beamline monochromators using topography test unit.. United States: N. p., 2007. Web.
Maj, J., Waldschmidt, G., Baldo, P., Macrander, A., Koshelev, I., Huang, R., Maj, L., Maj, A., Univ. of Chicago, Northeastern Ohio Univ. Coll. of Medicine, & Rosalind Franklin Univ. of Medicine and Science. Stress mitigation of x-ray beamline monochromators using topography test unit.. United States.
Maj, J., Waldschmidt, G., Baldo, P., Macrander, A., Koshelev, I., Huang, R., Maj, L., Maj, A., Univ. of Chicago, Northeastern Ohio Univ. Coll. of Medicine, and Rosalind Franklin Univ. of Medicine and Science. Mon . "Stress mitigation of x-ray beamline monochromators using topography test unit.". United States. doi:.
@article{osti_982024,
title = {Stress mitigation of x-ray beamline monochromators using topography test unit.},
author = {Maj, J. and Waldschmidt, G. and Baldo, P. and Macrander, A. and Koshelev, I. and Huang, R. and Maj, L. and Maj, A. and Univ. of Chicago and Northeastern Ohio Univ. Coll. of Medicine and Rosalind Franklin Univ. of Medicine and Science},
abstractNote = {Silicon and diamond monochromators (crystals), often used in the Advanced Photon Source X-ray beamlines, require a good quality surface finish and stress-free installation to ensure optimal performance. The device used to mount the crystal has been shown to be ajor contributing source of stress. In this case, an adjustable mounting device is an effective method of reducing stresses and improve the rocking curve to levels much closer to ideal. Analysis by a topography test unit has been used to determine the distribution of stresses and to measure the rocking curve, as well as create CCD images of the crystal. This paper describes the process of measuring these stresses and manipulating the mounting device and crystal to create a substantially improved monochromator.},
doi = {},
journal = {Adv. X-ray Anal.},
number = 2007,
volume = 50,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}

Conference:
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  • Projection X-ray topography of single crystals is a classic technique for the evaluation of intrinsic crystal quality of large crystals. In this technique a crystal sample and an area detector (e.g., X-ray film) collecting intensity of a chosen crystallographic reflection are translated simultaneously across an X-ray beam collimated in the diffraction scattering plane (e.g., [1, 2]). A bending magnet beamline of a third-generation synchrotron source delivering x-ray beam with a large horizontal divergence, and therefore, a large horizontal beam size at a crystal sample position offers an opportunity to obtain X-ray topographs of large crystalline samples (e.g., 6-inch wafers) inmore » just a few exposures. Here we report projection X-ray topography system implemented recently at 1-BM beamline of the Advanced Photon Source. A selected X-ray topograph of a 6-inch wafer of 4H-SiC illustrates capabilities and limitations of the technique.« less
  • Cryogenically cooled, single-crystal silicon, x-ray monochromators offer much better thermal performance than room-temperature silicon monochromators. The improved performance can be quantified by a figure-of-merit equal to the ratio of the thermal conductivity to the coefficient of thermal expansion. This ratio increases by about a factor of 50 as the temperature is decreased from 300 K to 100 K. An extensive thermal and structural finite element analysis is presented for an inclined, liquidnitrogen-cooled, Si monochromator crystal diffracting 4.2 keV photons from the [111] planes using Undulator A at the Advanced Photon Source. The angular size of the beam accepted on themore » crystal was chosen to be 50 {mu}rad vertically and 120 {mu}rad horizontally. The deflection parameter, K, was 2.17 for all cases. The peak power density at normal incidence to the beam was calculated to be 139 W/mm{sup 2}, and the total power was 750 W at a distance of 30 m from the source for a positron current of 100 mA. The crystal was oriented in the inclined geometry with an inclination angle of 85{degree} for all cases. The performance of the crystal was investigated for beam currents of 100, 200, and 300 mA. The calculated peak slopes of the diffraction plane over the extent of the beam footprint were {minus}1.17, {minus}2.35, and 0.33 {mu}rad, and the peak temperatures were 88.2, 102.6, and 121.4 K, respectively. The variation in the Bragg angle due to change in d-spacing across the beam footprint was less than 1 {mu}rad for all cases. These results indicate that a properly designed, cryogenically cooled, inclined silicon monochromator can deliver the full brilliance of Undulator A at even the highest machine currents.« less
  • The Topography X-ray Laboratory of the Advanced Photon Source (APS) at Argonne National Laboratory operates as a collaborative effort with APS users to produce high performance crystals for APS X-ray beamline experiments. For many years the topography laboratory has worked closely with an on-site optics shop to help ensure the production of crystals with the highest quality, most stress-free surface finish possible. It has been instrumental in evaluating and refining methods used to produce high quality crystals. Topographical analysis has shown to be an effective method to quantify and determine the distribution of stresses, to help identify methods that wouldmore » mitigate the stresses and improve the Rocking curve, and to create CCD images of the crystal. This paper describes the topography process and offers methods for reducing crystal stresses in order to substantially improve the crystal optics.« less
  • We report progress on implementation and commissioning of sequential X-ray diffraction topography at 1-BM Optics Testing Beamline of the Advanced Photon Source to accommodate growing needs of strain characterization in diffractive crystal optics and other semiconductor single crystals. The setup enables evaluation of strain in single crystals in the nearly-nondispersive double-crystal geometry. Si asymmetric collimator crystals of different crystallographic orientations were designed, fabricated and characterized using in-house capabilities. Imaging the exit beam using digital area detectors permits rapid sequential acquisition of X-ray topographs at different angular positions on the rocking curve of a crystal under investigation. Results on sensitivity andmore » spatial resolution are reported based on experiments with high-quality Si and diamond crystals. The new setup complements laboratory-based X-ray topography capabilities of the Optics group at the Advanced Photon Source.« less