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Title: Performance of cryogenically cooled, high-heat-load silicon crystal monochromators with porous media augmentation

Journal Article · · Review of Scientific Instruments
DOI:https://doi.org/10.1063/1.1147264· OSTI ID:389538
; ; ;  [1]
  1. Argonne National Laboratory, Advanced Photon Source, 9700 South Cass Avenue, Argonne, IL 60439 (United States)

The performance of two Si crystal x-ray monochromators internally cooled with liquid nitrogen was tested on the F2-wiggler beamline at the Cornell High Energy Synchrotron Source (CHESS). Both crystals were (111)-oriented blocks of rectangular cross section having identical dimensions. Seven 6.4-mm-diameter coolant channels were drilled through the crystals along the beam direction. In one of the crystals, porous Cu mesh inserts were bonded into the channels to enhance the heat transfer. The channels of the second crystal were left as drilled. Symmetric, double-crystal rocking curves were recorded simultaneously for both the first and third order reflections at 8 and 24 keV. The power load on the cooled crystal was adjusted by varying the horizontal beam size using slits. The measured Si(333) rocking curve of the unenhanced crystal at 24 keV at low power was 1.9 arcsec FWHM. The theoretical width is 0.63 arcsec. The difference is due to residual fabrication and mounting strain. For a maximum incident power of 601 W and an average power density of about 10 W/mm{sup 2}, the rocking curve was 2.7 arcsec. The rocking curve width for the enhanced crystal at low power was 2.4 arcsec. At a maximum incident power of 1803 W and an average power density of about 19 W/mm{sup 2}, the rocking curve width was 2.2 arcsec FWHM. The use of porous mesh augmentation is a simple, but very effective, means to improve the performance of cryogenically cooled Si monochromators exposed to high power x-ray beams. {copyright} {ital 1996 American Institute of Physics.}

Research Organization:
Argonne National Lab. (ANL), Argonne, IL (United States)
DOE Contract Number:
W-31109-ENG-38
OSTI ID:
389538
Report Number(s):
CONF-9510119-; ISSN 0034-6748; TRN: 96:027939
Journal Information:
Review of Scientific Instruments, Vol. 67, Issue 9; Conference: SRI `95: synchrotron radiation instrumentation symposium and the 7. users meeting for the advanced photon source (APS), Argonne, IL (United States), 16-20 Oct 1995; Other Information: PBD: Sep 1996
Country of Publication:
United States
Language:
English