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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.
X-ray Absorption Spectroscopy
|Main Scientific Disciplines||
Structural Molecular Biology
|Beam Line Specifications|
20-pole, 2-Tesla wiggler, 0.8 mrad beam
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
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.
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|
|Beam Line Phone||
650-926-5273. On-site Users: Contact the Duty Operator at 9-926-4040
|Beam Line Contact|
Content Owner: N Stojanovic | Last updated: 04/22/2017