First Optics Enclosure
The First Optics Enclosure (FOE), as the name implies, is the first enclosure or station the X-ray beam encounters on the experimental floor of the APS in our sector. It houses most of the beam conditioning optics, which prepare the high-power X-ray for a particular experiment.
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
Theoretical Flux Through The Working Aperture:
Photon Energy (keV) |
Harmonic |
Flux (phot/sec/0.1%BW) |
| 10 | 1 | 4×1014 |
| 30 | 3 | 5×1013 |
| 50 | 5 | 7×1012 |
| 70 | 7 | 1×1012 |
Facility Contacts
Mrinal Bera
Anomalous Small Angle X-ray Scattering
(630) 252-0472
mrinalkb@uchicago.edu
Wei Bu
Liquid Surface/Interface
(630) 252-0470
weibu@uchicago.edu
Natalie Chen
NSF’s ChemMatCARS Sector User Coordinator
(630) 252-0476
nataliec@uchicago.edu
Yu-Sheng Chen
Beamline Operations Manager
Advanced Crystallography
(630) 252-0471
yushengchen@uchicago.edu
Binhua Lin
Executive Director and Project Manager
(630) 252-0463
blin@uchicago.edu
Mati Meron
Beamline Optics
(630) 252-0478
mmeron@uchicago.edu