Experimental Station 4-1

Beam line 4-1 is a high-flux station optimized for x-ray absorption spectroscopy and EXAFS experiments requiring x-rays with energies between ~ 6 and 38 keV.  This energy range includes most of the transition metals (all rows), lanthanides and actinides, P-block elements, alkaline and alkaline earths. While it is possible to access x-rays as low as 5 keV, these experiments are challenging because of air absorption and are better performed at beam line 4-3. BL 4-1 can accommodate samples containing uranium and other radionuclides, depending upon their radiotoxicity level, activity, shielding requirements, and complexity of the experimental requirements.  See additional information below under Sample Environment. The beamline offers low temperature measurements (LN2 and LHe) and a 30-element Ge detector system.

Status
Open
Supported Techniques
X-ray Absorption Spectroscopy
Main Scientific Disciplines
Bioscience
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 5500-38000 eV 1 x 10-4 4 x 18mm 2 x 1012
Collimated 5000-23000 eV 1 x 10-4 2 x 18mm 2 x 1012

 

Optics

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

Monochromator: LN2 cooled, Si(220), ϕ = 0o & 90o. double-crystal, variable-exit geometry

Absorption

N/A

Instrumentation

Detectors: ionization chambers, Lytle-type fluorescence-yield ion chamber detector, Canberra 30-element Ge solid-state, Vortex SiLi solid state detector for special detection geometry requirements.

Cryostat: Oxford Liq-He, LN cryostat for magazine capability and radioactive samples

Other: Soller slits and scatter-guards, Goniometers for grazing-incidence XAS

Sample Environment

Ambient pressure experiments

Sample temperature: 10-200 K (cryostats)

Sample size: 3 x 20 x 1 mm (standard powder cell), flat wafers up to 2.5 cm diam

Minimum Sample Requirement: 1 mM, 100 μl solutions; 100 ppm, 10mg solids

Radioactive Samples: Users interested in running such samples should refer to the SSRL safety radioactive sample safety page  http://www-ssrl.slac.stanford.edu/content/safety/radioactive-materials-ssrl).  For more information, please contact Matt Padilla (3861).  Radioactive materials (RAM) users should be aware of the following important points (that often trip up first-time users):

* Advanced notifications of your intent to ship RAM are required 30-, 7-, and 1-days in advance.

* Only approved holders listed in the SSRL radioactive sample holder catalog may be used.

* Shipping containers and practices must conform closely to the instructions provided to users following submission of you 7-day notifications.

* ALL samples containing radioisotopes are considered to be RAM by DOE, and we are required to control their movement on site. This requirement would include, for example, natural samples containing only 20 ppm of natural U. For this reason, ALL RAM samples require advanced notification and approval prior to shipment. Please help us  comply with these requirements by providing full information regarding the isotope compositions and activities of your samples when you request beam time and submit your notifications.

Data Acquisition and Analysis

XASSERV, EXAFSPAK, SixPAK, µscan GUI.

X-ray Data Booklet

Beam Line Phone
650-926-5241. On-site Users: Contact the Duty Operator at 9-926-4040
Beam Line Contact
Beam Line Engineering Notes

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