Experimental Station 7-3

Beam line 7-3 is a wiggler side-station dedicated for x-ray absorption spectroscopy and EXAFS measurements on dilute biological systems. BL7-3 is equipped with a 30-element Ge solid-state detector in addition to ionization chambers and Lytle/PIPS detectors. A dedicated LHe cryostat allows for routine low temperature measurements. The unfocused beam on BL7-3 is ideal for samples especially susceptible to radiation damage, such as high-valent intermediates and other oxidized species.

Supported Techniques
X-ray Absorption Spectroscopy
Main Scientific Disciplines
Biomedical Sciences
Structural Molecular Biology
Beam Line Specifications


20-pole, 2-Tesla wiggler, 0.8 mrad beam

  Energy Range Resolution ΔE/E Spot Size Flux
Unfocused 5400-32000 eV 1 x 10-4 2 x 15 mm2 ~1 x 1012



M0 mirror: Flat, bent, vertically collimating, 1 m, Si, Rh-coated

Monochromator: LN2 cooled, Si(220), ϕ = 0o & 90o, double-crystal, non-fixed exit slit

Monochromator Crystal Glitch Library 

Crystal changes need to be scheduled and coordinated in advance with BL support staff


762 microns Be, 205 microns C


Detectors: Ionization chambers, PIPS, Lytle, Canberra 30-element Ge solid-state

Cryostat: Oxford Helium cryostat, cooled either by closed-cycle cooled He gas loop (10-100 K) or by open-cycle liquid He dewar (4-200 K).

Other: Shutter and variable filters to alleviate beam damage. Soller slits and scatter-guard, multiple-sample changer for room temperature samples. Multiple-sample holder for room temperature samples. Automatic scan queueing available for multiple room temperature samples and/or multiple spots on cold samples.

Sample Environment

Ambient pressure experiments

Sample temperature: 10-100 K (default configuration, He cryostat with closed-cycle cooled He gas loop) or 4-200 K (He cryostat with open-cycle liquid He dewar) or room temperature (no cryostat).  Please indicate sample temperature choice on Beam Time Request (BTR) form to avoid setup delays.

Sample size: 5 x 20 mm max

Minimum Sample Requirement: 500 μM, 100 μl solutions; 10 ppm, 10 mg solids

Data Acquisition and Analysis

Web-XAS Data Collector, EXAFSPAK, SixPAK.

X-ray Data Booklet

Beam Line Phone
650-926-5273. On-site Users: Contact the Duty Operator at 9-926-4040
Beam Line Contact

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