Experimental Station 4-3

Beam line 4-3 is a wiggler side-station dedicated for x-ray absorption spectroscopy and EXAFS measurements on biological, environmental, catalysis, and materials systems. This station enables tender x-ray measurement (S K-edge and up, i.e. 2.4-5 keV) in addition to hard x-rays ( up to 11 keV).  It is setup with a He flight path from the beam line optics to the sample. The beam is collimated and unfocused to allow for high energy-resolution measurements on homogenous samples. BL4-3 is equipped with a 4-element solid-state silicon drift detector in addition to ionization chambers and PIPS/Lytle detectors. A LHe cryostream allows for low-temperature measurements. A motorized sample holder stage allows sequential measurement on multiple samples.  Infrastructure for in-situ catalysis with mass-flow control and reactor cells have recently been added.  

Status
Open
Supported Techniques
X-ray Absorption Spectroscopy
Main Scientific Disciplines
Bioscience
Catalysis
Environmental Sciences
Materials Sciences
Beam Line Specifications

Source

20-pole, 2.0-Tesla Wiggler, 0.75 mrad, Side station

  Energy Range Resolution ΔE/E Spot Size Flux
Unfocused 2400-11000 eV 1 x 10-4 2 x 12 mm2 1 x 1012 

 

Optics

M0 mirror: vertically collimating, flat, bent, 1.0 m, bare Si, cutoff ~10.5 keV

Monochromator:  LN2 cooled, Si(111), 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

Absorption

127 micron Be

Instrumentation

Detectors: Ionization chambers, PIPS, Lytle, Hitachi HTA 4-element solid-state Si drift detector, electron-yield detector

Cryostat: LHe cryostream

Other: He-purged sample box. He flow meters and oxygen content meter on sample space. Automated shutter to alleviate beam damage. Motorized multiple solid-sample holder.  Gas cabinet, mass flow control, reactor cells for in-situ catalysis.

Sample Environment

Ambient He atmosphere in gas tight sample box (room temperature) plastic sample compartment (for He cryostream)

Sample temperature: 20-50 K (He cryostream) or Room temperature (no cryostat)

Sample size: 5 X 20 mm

Minimum Sample Requirement: 2-5 mM, 200 ul or 100 ppm, 2-5 mg at tender energies. 2 mM, 200 μl solutions or 10 ppm, 10 mg solids at higher energies. Automatic scan queueing available for multiple room temperature samples and/or multiple spots on cold samples.

For catalysis: reactor cells.

Data Acquisition and Analysis

WebXAS Data Collector, EXAFSPAK, SixPAK
X-ray Data Booklet

Beam Line Phone
650-926-5243. On-site Users: Contact the Duty Operator at 9-926-4040
Beam Line Contact

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