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 BL4-3. BL4-1 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 beam line offers low temperature measurements (LN2 and LHe) and a 30-element Ge detector system.
| Status | Open |
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| Supported Techniques | X-ray Absorption Spectroscopy |
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| Main Scientific Disciplines | Catalysis Environmental Sciences Materials Sciences |
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| Beam Line Specifications | ||||||||||||||||
Source20-pole, 2.0-Tesla Wiggler, 0.75 mrad, side station
OpticsM0 mirror: vertically collimating, flat, bent,1 m, Si, Rh-coated Monochromator: LN2 cooled, Si(220), ϕ = 0o & 90o. double-crystal, variable-exit geometry AbsorptionN/A |
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| 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 |
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| 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 (x3861). 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. |
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| Data Acquisition and Analysis | XASSERV, EXAFSPAK, SixPAK, µscan GUI. |
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| Beam Line Phone | 650-926-5241. On-site Users: Contact the Duty Operator at 9-926-4040 |
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