Source Parameters

X-ray source: APS undulator A, 72 periods, period length 33mm, provides continuous energy coverage from ~3keV to (theoretically) well above 100keV.
Electron beam size (σ values): 270μm horizontal, 8.6μm vertical.
Electron beam divergence (σ values): 11.4μr horizontal, 2.9μr vertical.
- Note: The X-ray source dimensions are somewhat larger than the values above, due to radiative effects. The extent of the radiative “bloat” depends on x-ray energy, becoming negligible for high energies.

Bruker cryogenically cooled double crystal monochromator, using pairs of Si (111) or Si (311) crystals.
Energy range : 5-36keV with Si (111), 10-70keV with Si(311)
Bandwidth: 1.3×10^-4 with Si (111), 2.8×10^-5 with Si (311)
Bruker mirror system, consisting of vertically focusing bimorph mirror and vertically deflecting flat silicon mirror. Coated with 3 stripes, as follows:
- SiO2 – energies below 12 keV
- Rh – energies between 12-23 keV
- Pt – energies above 23 keV

Yu-Sheng Chen
Advanced Crystallography
(630) 252-0471
yschen@cars.uchicago.edu

Wei Bu
Liquid Surfaces/Interference
(630) 252-0470
bu@cars.uchicago.edu