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Title: Study of a scattering shield in a high heat load monochromator

;  [1];  [2]
  1. (UC)
  2. (
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Nucl. Instrum. Methods A; Journal Volume: 716; Journal Issue: 07, 2013
Country of Publication:
United States

Citation Formats

Huang, Rong, Meron, Mati, and HWMRI). Study of a scattering shield in a high heat load monochromator. United States: N. p., 2014. Web. doi:10.1016/j.nima.2013.03.037.
Huang, Rong, Meron, Mati, & HWMRI). Study of a scattering shield in a high heat load monochromator. United States. doi:10.1016/j.nima.2013.03.037.
Huang, Rong, Meron, Mati, and HWMRI). 2014. "Study of a scattering shield in a high heat load monochromator". United States. doi:10.1016/j.nima.2013.03.037.
title = {Study of a scattering shield in a high heat load monochromator},
author = {Huang, Rong and Meron, Mati and HWMRI)},
abstractNote = {},
doi = {10.1016/j.nima.2013.03.037},
journal = {Nucl. Instrum. Methods A},
number = 07, 2013,
volume = 716,
place = {United States},
year = 2014,
month = 2
  • Undulators installed in third-generation synchrotron radiation facilities will provide photon beams with high brilliance and large power densities. The optical quality of these beams allows, in principle, the use of simpler optical systems for focusing and monochromatization. In practice the performance of the optical elements is the physical limit to the exploitation of these high brilliance beams. In double-crystal monochromators the bending of the first crystal due to the thermal load and the anticlastic effect on the sagittally bent second one are among the main sources of problems on the overall performances. Here we have considered a double-crystal monochromator withmore » a meridionally bent first crystal followed by a sagittally focusing one. We show that this geometry offers correction either of thermal loads and anticlastic distortions, or minimization of the bandpass or tangential focusing. This can be particularly useful on the high-energy range and for sharp Bragg reflections.« less
  • Conventional minichannel water cooling geometry will not perform satisfactorily for x-radiation from a wiggler source at the Advanced Photon Source. For closed-gap wiggler operation, cryogenic silicon appears to be the only option for crystals in Bragg-Bragg geometry. For operation of the wiggler at more modest critical energies ({lt}17 keV), the first crystal can be cooled by a pin-post cooling scheme, using water at room temperature as a coolant. In order to limit the water consumption to 4 gpm and hence the risk of introducing vibrations to the crystal, the intensely cooled area of the crystal was matched to the footprintmore » of the beam, leaving a less cooled area of the crystal subject to survival in a missteered beam but not to perform as a monochromator. The manifold design avoids large areas of high water pressure that would bow the crystal. We present here the design of a pin-post monochromator consisting of a four-layer silicon manifold system and an integrally bonded 39{percent} nickel-iron alloy base plate. A transparent prototype of the design will be exhibited. Fabrication techniques and design advantages will be discussed. {copyright} {ital 1996 American Institute of Physics.}« less
  • The use of water-cooling channels in silicon x-ray monochromators for the Cornell High Energy Synchrotron Source (CHESS) high power wiggler beamlines has been studied by finite element analysis. The efficiency from channels of different dimensions, ranging from 25 mm to 2 mm width and 5 mm depth, has been calculated. The new crystals are designed to replace the indirect cooled monochromators currently used at CHESS wiggler stations. At typical operation parameters of 150 mA electron current at 5.3 GeV and a gap of 40 mm, the 24-pole wiggler at CHESS provides an x-ray beam with a total power of 2.7more » kW at the monochromator. Procedures have been developed for fabrication of internally cooled crystals using a silver-glass dye attach paste. Tests of a new crystal with a conventional x-ray source revealed very small amounts of residual strain. Experiments with synchrotron radiation are scheduled in the near future. {copyright} {ital 1996 American Institute of Physics.}« less
  • The high heat load associated with the powerful and concentrated x-ray beams generated by insertion devices (IDs) at a number of present and many of the future (planned or under construction) synchrotron radiation facilities poses a formidable engineering challenge for the design of monochromators and other optical devices. Successful utilization of the intense x-ray beams from insertion devices depends critically on the development, design, and availability of optical elements that provide acceptable performance under high heat load. Present monochromators can handle, at best, heat load levels that are an order of magnitude lower than those generated by these IDs. Themore » monochromator described here, and referred to as the inclined'' monochromator, can provide a solution to the high heat load problem. The inclined monochromator is different in a number of aspects from other conventional monochromator designs. Its primary differentiating characteristic is in the orientation of the diffracting planes. In this geometry, the crystal surface normal and the normal to the diffracting crystal planes make an angle close to 90{degree}. This leads to a number of interesting effects including spreading of the beam over a very large area (effectively reducing the incident heat flux), and also rendering a much smaller effective slope error. Thus, a substantial enhancement in the performance of the monochromator is realized. The preliminary results of a comparative numerical simulation of the performance of the inclined monochromator under the 5-kW power undulator A beam at the Advanced Photon Source are encouraging and provide a quantitative estimate of the expected enhancement.« less
  • Analytical solutions for the temperature distribution and displacement field gradients in the high heat load monochromator are presented. The footprint of the incident x-ray beam on the crystal surface is approximated by an infinitely long narrow strip, which is applicable in the case of the inclined diffraction geometry. The two-dimensional problem in the cross section of the crystal normal to the footprint is considered. The solutions for the temperature distribution and displacement field gradients are found in terms of Fourier integrals. These expressions are also valid for x-ray mirrors. The deviation of the incident beam from exact Bragg position producedmore » by this deformation is calculated. All numerical examples are calculated for the special undulator which is to be installed in the sector III of the Advanced Photon Source.« less