Experimental Station 11-2

Beam line 11-2 is a high-flux XAS station dedicated to molecular biogeochemical and interface sciences. It is optimized for challenging XAS measurements on dilute or radioactive samples, single crystals, and interfaces. To support these experiments, BL11-2 is equipped with collimating and focusing optics, a "double double" Si(220) LN2-cooled monochromator, and a 100-element solid state Ge detector array. Additional instrumentation includes LHe and LN2 cryostats, a grazing incidence XAS spectrometer, and HEPA-filtered controlled exhaust systems that are continuously monitored to detect the presence of air-born radioactivity. It has an adjacent sample preparation room for handling and temporary storage of radioactive samples. BL11-2 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.

Status
Open
Supported Techniques
X-ray Absorption Spectroscopy
Grazing incidence x-ray absorption spectroscopy
Main Scientific Disciplines
Environmental Sciences
Beam Line Specifications

Source

26-pole, 2.0-Tesla Wiggler ID End Station, ≤1.5 mrad variable acceptance

  Energy Range Resolution ΔE/E Spot Size Flux
Focused 5000-20000 eV 1 x 10-4 0.5 x 1 mm2 2 x 1012
Unfocused 5000-37000 eV 1 x 10-4 3 x 30 mm2 2 x 1012
Collimated 5000-23000 eV 1 x 10-4 2 x 30 mm2 2 x 1012

 

Optics

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

M1 mirror: Bent cylindrical, 1 m, Si, Rh-coated, ~1:1 focusing

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

Monochromator Crystal Glitch Library 

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

Absorption

N/A

Instrumentation

Detectors: Ionization chambers, Lytle-type fluorescence-yield ion chamber detector, Canberra 100-pixel Ge solid-state monolith, Vortex SiLi solid state detector for special detection geometry requirements.

Cryostat: Oxford LHe, LN2 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: 500 μM, 100 μl solutions; 20 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 to 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
650-926-8650. On-site Users: Contact the Duty Operator at 9-926-4040
Beam Line Contact
Beam Line Engineering Notes

Find Stanford Synchrotron Radiation Lightsource on FlickrFind Stanford Synchrotron Radiation Lightsource on YouTubeFind Stanford Synchrotron Radiation Lightsource on Twitter