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Beamline 21-ID-G: Insertion Device Beamline

Life Sciences


LS-CAT, APS Sector 21,uses canted undulators to provide two independent sources for four ID end stations: 21-ID-D, 21-ID-E, 21-ID-F, and 21-ID-G. All four stations can be used simultaneously and independently. The 21-ID-F station supports macromolecular crystallography and SAD phasing at selenium ONLY as this is a FIXED WAVELENGTH STATION. All LS-CAT experimental stations are equipped with MD-2 diffractometers with state-of-the-art features such as on-axis sample viewing with precision zoom, automatic sample alighment, omega/kappa/phi motions, and a tuned piezoelectric fast shutter. Additional capabilities include kappa offset, a full suite of data analysis tools for on-line data analysis, stable sample table with separate detector table allowing sample-to-detector distance changes without realignment, and sample centering (3-click or automatic).      


Supported Techniques

  • Macromolecular crystallography

Beamline Controls and Data Acquisition

MD-2 diffractometer software from EMBL (with LS-CAT developed extensions) for sample mounting, centering, beamline diagnostics, and data colection. VME EPICS/MEDM low-level interface, PMAC Turbo motion control, and Linus workstations for data collection and processing.


  • MAR 300 CCD
  • Bruker-AXS XFlash 1001 SSD for fluorescence spectroscopy

Additional Equipment

  • MD2 Microdiffractometer
  • CATS Sample Changer: SPINE or Actor pucks

Local Contacts

Name KEITH E. BRISTER (Operations Manager)
Phone 630.252.

Beamline Specs


3.0 Undulator

Monochromator Type


Energy Range

12.7- keV

Resolution (ΔE/E)

2 x 10 -4

Flux (photons/sec)

1 x 1012 @12.7 keV

Beam Size (HxV)


50µm x 50µm

For additional information see:

Current Status:

Operational/Accepting General Users

Access Mode:

Remote On-site Mail-in