Beam line 4-2 is a small-angle scattering/diffraction station dedicated to structural biology studies primarily on non-crystalline systems. The instrument features a pin-hole geometry SAXS camera, which can be semi-automatically configured to have one of seven sample-to-detector distances between 0.25m and 3.5m. This allows to tune and optimize the instrument to the experimental needs. A Pilatus3 X 1M is the primary detector used at the beamline. It features a large active area, photon counting x-ray detection and a 500Hz maximum frame rate which also allows fast Time-resolved studies at BL4-2. A large area gap-less Rayonix225HE ccd-detector is also available for experiments that require smaller pixel sizes and a detection area without gaps. The facility provides a large selection of specialized sample handling devices, such as a stopped-flow rapid mixer, a high-throughput automated sample changer for solution scattering, a size-exclusion chromatography coupled solution SAXS setup among others.
| Status | Open |
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| Supported Techniques | Biological Small-angle X-ray Scattering (BioSAXS) Fiber diffraction Lipid membrane diffraction Small-angle single crystal diffraction Time-resolved biological SAXS |
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| Main Scientific Disciplines | Biomedical Sciences Bioscience Structural Molecular Biology |
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| Beam Line Specifications | |||||||||||||||||
Source20-pole, 2.0-Tesla Wiggler ID End Station
OpticsM0 mirror: bent cylinder 15.4m vertical radius (adjustable) and 57 mm horizontal radius Rh-coated silicon (cutoff energy 17.5 keV) mean angle of incidence: 3.8 mrad Magnification 1.0, upward reflecting Monochromator(s): liquid N2 cooled Si(111) and Mo/B4C multilayer AbsorptionN/A |
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| Instrumentation | Detectors: Pilatus3 X 1M, Rayonix225HE, Vortex detector Intensity monitor: photodiode in beamstop for transmitted intensity, APD for incident intensity Slits: JJ-Xray beam defining and guard slits, Xenocs scatterless guard slit in front of sample Other: mirror pitch feedback for beam stability, variable filters, fast shutter, variable length flight path Angular range (at 11 keV, 4 mm beamstop):
Please refer to http://ssrl.slac.stanford.edu/~saxs |
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| Sample Environment | Autosampler (automated liquid sample loader): Sample volume: 10 ul – 30 ul Temperature range: 5 C – 40 C Manual loading (flow) cell: Sample volume: 10 ul – 30 ul Temperature range: 5 C – 40 C Stopped-flow mixer (for fast time-resolved solution SAXS) : Sample volume: 30 ul – 100 ul (per shot) Temperature range: 5 C – 70 C Mixing deadtime: ~1 ms Humidity Chamber (for lipid diffraction and GiSAXS) : Sample temperature range: 10 C – 50 C rH range: 30% - 100% |
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| Data Acquisition and Analysis | Data acquisition: Blu-ice |
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| Beam Line Phone | 650-926-5242. On-site Users: Contact the Duty Operator at 9-926-4040 |
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| Beam Line Contact | |||||||||||||||||
