Advanced controller upgrade in a double crystal monochromator at the SIRIUS beamline in synchrotron SOLEIL

The requirement for vibrational stability of beamline optics continues to evolve rapidly to comply with the demands created by the improved brilliance of the third-generation low-emittance storage rings around the world. The challenge is to quantify the performance of the instrument before it is installed at the beamline. In this article, measurement techniques are presented that directly and accurately measure (i) the relative vibration between the two crystals of a double-crystal monochromator (DCM) and (ii) the absolute vibration of the second-crystal cage of a DCM. Excluding a synchrotron beam, the measurements are conducted underin situconditions, connected to a liquid-nitrogen cryocooler. The investigated DCM utilizes a direct-drive (no gearing) goniometer for the Bragg rotation. The main causes of the DCM vibration are found to be the servoing of the direct-drive goniometer and the flexibility in the crystal cage motion stages. It is found that the investigated DCM can offer relative pitch vibration down to 48 nrad RMS (capacitive sensors, 0–5 kHz bandwidth) and absolute pitch vibration down to 82 nrad RMS (laser interferometer, 0–50 kHz bandwidth), with the Bragg axis brake engaged.

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Double-crystal diffraction imaging with a small effective divergence source: application to the magneto-acoustic vibrations in FeBO3

Journal of Applied Crystallography ◽

10.1107/s0021889800004222 ◽

2000 ◽

Vol 33 (4) ◽

pp. 1051-1058

Author(s):

Ioanna Matsouli ◽

Vladimir V. Kvardakov ◽

José Baruchel

Keyword(s):

Synchrotron Radiation ◽

Spatial Dispersion ◽

Angular Size ◽

Standing Waves ◽

Bragg Diffraction ◽

Elastic Coupling ◽

Acoustic Vibrations ◽

Double Crystal ◽

Double Crystal Monochromator ◽

Diffraction Imaging

Ultrasonic standing waves, excited in FeBO3(111) crystal plates through magneto-elastic coupling, were visualized using monochromatic Bragg diffraction imaging (topography) with synchrotron radiation. The images depend strongly on whether diffraction by the sample occurs in the same plane as in the double-crystal monochromator, or in the perpendicular plane. The observations are explained by taking into account (a) the strong spatial dispersion which prevails because of the small effective divergence (angular size of the source as seen from a point in the specimen), which is less than one microradian in this experiment, and (b) the sample vibration and curvature.

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An accurate theory of X-ray coplanar multiple SRMS diffractometry

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273318012615 ◽

2018 ◽

Vol 74 (6) ◽

pp. 673-680 ◽

Cited By ~ 1

Author(s):

V. G. Kohn

Keyword(s):

Synchrotron Radiation ◽

Plane Wave ◽

Experimental Setup ◽

Incident Plane Wave ◽

Instrumental Function ◽

Multiple Diffraction ◽

Double Crystal ◽

X Ray ◽

Double Crystal Monochromator ◽

Incident Plane

The article reports an accurate theory of X-ray coplanar multiple diffraction for an experimental setup that consists of a generic synchrotron radiation (SR) source, double-crystal monochromator (M) and slit (S). It is called for brevity the theory of X-ray coplanar multiple SRMS diffractometry. The theory takes into account the properties of synchrotron radiation as well as the features of diffraction of radiation in the monochromator crystals and the slit. It is shown that the angular and energy dependence (AED) of the sample reflectivity registered by a detector has the form of a convolution of the AED in the case of the monochromatic plane wave with the instrumental function which describes the angular and energy spectrum of radiation incident on the sample crystal. It is shown that such a scheme allows one to measure the rocking curves close to the case of the monochromatic incident plane wave, but only using the high-order reflections by monochromator crystals. The case of four-beam (220)(331)({\overline {11}}1) diffraction in Si is considered in detail.

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A low-cost and flexible double-crystal monochromator for an x-ray beamline

Review of Scientific Instruments ◽

10.1063/1.1148755 ◽

1998 ◽

Vol 69 (3) ◽

pp. 1230-1235 ◽

Cited By ~ 3

Author(s):

C. S. Hwang ◽

F. Y. Lin ◽

Chih-Hao Lee ◽

Kuan-Li Yu ◽

C. H. Hsieh ◽

...

Keyword(s):

Low Cost ◽

Double Crystal ◽

X Ray ◽

Double Crystal Monochromator

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A double crystal monochromator with self-compensation mechanism for ELETTRA XRD2 beamline

Diamond Light Source Proceedings ◽

10.1017/s2044820110000377 ◽

2010 ◽

Vol 1 (MEDSI-6) ◽

Author(s):

A. Gambitta

Keyword(s):

Vertical Displacement ◽

Compensation Mechanism ◽

Input Beam ◽

Output Beam ◽

Double Crystal ◽

X Ray ◽

New Device ◽

Double Crystal Monochromator ◽

Fixed Distance

A prototype of a new double crystal monochromator (DCM) has been designed and developed for the second crystallography beamline (XRD2) at ELETTRA. The new device has to cover the 8–35 keV X-ray range. Since the corresponding diffraction angles are quite small, the choice has been to design a DCM with a fixed distance between the two crystals. As a consequence, the output beam has a small vertical displacement during the scan. This movement is compensated by means of an upstream mask, vertically moving and cutting the input beam at different heights. The movement of the mask is driven by a mechanism linked to the primary rotation of crystals (self-compensation), without any additional motor and following the displacement law required for compensation. The principle, the mechanism and the general mechanical concept of the device will be described in this paper.

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