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Persistent URL http://purl.org/net/epubs/work/23537
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Record Id 23537
Title Soft X-ray beamline for surface EXAFS studies in the energy range 60 equal to or less than 11100 eV at the Daresbury SRS
Abstract The characteristics of the beamline used for EXAFS (Extended X-ray Absorption Fine Structure) studies at the Daresbury Synchrotron Radiation Source are described. Monochromatic photons are available in the photon energy range 60<hr<11100eV. This has been achieved using a monochromator with a combination of crystal and grating optics. The radiation is focussed through the monochromator by a toroidal premirror at 0.5 degree grazing angle. Three pairs of crystals and a plane grating with focussing mirror are available which can be interchanged under UHV. The plane grating/mirror monochromator has two ranges of zero-order angles 6.4 and 2, giving photon energy ranges of 60-550eV and 600-2000eV respectively with a 1200mm-2 grating. The crystals in use are InSb(111), Ge(111) and Ge(220) having photon energy ranges of 1745-7360eV, 2000-8430eV and 3260-11100eV. The performance of the gratings and crystals in respect of intensity, resolution, scattered light and higher orders is discussed and some representative results from the beamline are given. Detailed consideration has been given to thermal effects on the crystal and grating optics. The grating can be exposed to a maximum power density of 9W cm-2 and has so far performed adequately. The crystals, which can see power densities of up to 150W cm-2 have survived, but beam exit movement and energy scale shifts have been observed. Efforts to reduce these beam movement effects have been successful insomuch as the instruments is useable. InSb crystals suffered some radiation damage. Beryl and Quartz crystals have been tried but did not survive. Recommendations for the elimination of these beam heating effects are given, along with future improvements to reduce beam size at the sample for the grating/mirror part of the instrument.
Organisation SRS , SERC
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Language English (EN)
Type Details URI(s) Local file(s) Year
Report DL/SCI/P507E. 1986. 1986
Report DL Technical Reports DL-SCI-TM48E. 1986. DL-SCI-TM48E.pdf 1986
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