Stanford Synchrotron Radiation Lightsource

File:SSRL.png

Aerial photograph showing the SSRL facility, storage (left) and booster ring (right).

Photograph inside the SSRL accelerator ring.

Historic SSRL 1972. First x-ray beamline.

The Stanford Synchrotron Radiation Lightsource (formerly Stanford Synchrotron Radiation Laboratory), a division of SLAC National Accelerator Laboratory, is operated by Stanford University for the Department of Energy. SSRL is a National User Facility which provides synchrotron radiation, a name given to electromagnetic radiation in the x-ray, ultraviolet, visible and infrared realms produced by electrons circulating in a storage ring (SPEAR) at nearly the speed of light. These extremely bright x-rays can be used to investigate various forms of matter ranging from objects of atomic and molecular size to man-made materials with unusual properties. The obtained information and knowledge is of great value to society, with impact in areas such as the environment, future technologies, health, and education.^[1]

The SSRL provides experimental facilities to some 2,000 academic and industrial scientists working in such varied fields as drug design, environmental cleanup, electronics, and x-ray imaging.^[2]

History

In 1972 the first x-ray beamline was constructed by Ingolf Lindau and Piero Pianetta as literally a "hole in the wall" extending off of the SPEAR (Stanford Positron Electron Asymmetric Ring) storage ring. At that time, the SPEAR had been built in an era of particle colliders, where physicists were more interested in smashing protons together for hopes of discovering antimatter then using x-ray radiation for solid state physics and chemistry. From those meager beginnings the Stanford Synchrotron Radiation Project (SSRP) had begun. Within a short time SSRP had five experimental hutches sharing the radiation of only a few inches of the curved SPEAR dipole magnets. Each one of those stations was equipped with a monochromator to select the radiation of interest, and experimenters would bring their samples and end stations from all over the world to study the unique effects only achieved through synchrotron radiation. Today the SPEAR storage ring is dedicated completely to the Stanford Synchrotron Radiation Lightsoruce which currently is housed inside the SLAC facility. SSRL currently operates 24/7 for nine solid months out of the year, the other three are used for major maintenance issues and upgrades where direct access to the storage ring is needed, with 32 unique experimental stations which are made available to users from universities, government labs, and industry from all over the world.

Directors

1. Sebastian Doniach 1973-1977
2. Arthur Bienenstock 1978-1998
3. Keith Hodgson 1998-2005
4. Joachim Stöhr 2005-

Facilities

listed by Beamline and Station

• BL 7-3, 9-3, 4-3 These three beamlines are dedicated to biological x-ray absorption spectroscopy. Beamline 7-3 is an unfocused beamline and thus is best suited for XAS on dilute protein samples. Beamline 9-3 has an additional upstream focusing mirror, over 7-3, making it the preferred choice for photo reducing samples or ones where multiple different spots are needed. Beamline 4-3 was newly reopened as of 4/6/2009 bringing special capabilities for soft-energy (2.4-6 keV) studies in addition to hard x-rays. Beamline 4-3 now replaces 6-2 as the preferred location for Sulfur K-edge experiments at SSRL.
• BL 6-2 With three upstream mirrors, two for focusing and a third for harmonic rejection, this beamline has become dedicated to soft x-ray absorption spectroscopy including Rapid-scanning xRF imaging, and advanced spectrscopy such as XES (resonant and non-resonant x-ray emission spectroscopy), XRS (non-resonant x-ray Raman scattering and RIXS (resonant inelastic X-ray scattering).
• BL 8-2, 10-1, 13-2 These three beamlines are specialized for soft x-ray absorption spectroscopy, including NEXAFS (Near edge X-ray absorption fine structure), some light atom Ligand K-edge (carbon, nitrogen, oxygen, chlorine), PES (Photoemission spectroscopy), and L-edge measurements. All experiments on these beamlines require special handling and advanced ultra high vacuum experience and techniques.
• BL 11-3 Materials Science Scattering, Reflectivity and Single Crystal Diffraction Experiments. Uses to date include: study of structure in organic, metal, and semiconductor thin films and multilayers; study of charge-density waves in rare earth tri-tellurides; study of in-situ growth of biogenic minerals; partial determination of texture in recrystallized pumice; quick determination of single crystal orientation.^[3]
• BL 1-5, 7-1, 9-1, 9-2, 11-1, 11-3, 12-2 These beamlines are used for macromolecular x-ray crystallography. All of the beamlines are for general use, except for beamline 12-2, which was funded in part by Caltech via a gift from the Gordon and Betty Moore Foundation. As a result, 33% of beamtime on 12-2 is reserved for Caltech researchers.

External links

• SSRL Headline News A Monthly Digital Publication
• Lightsources.org
• Archives and History Office - Stanford Synchrotron Radiation Project (SSRP)

References

1. ^ SSRL Home page
2. ^ Woods, Heather Rock (September 27, 2005). "Stöhr to Direct Synchrotron Radiation Lab". Press Release. Menlo Park, CA: Stanford Linear Accelerator Center. Retrieved September 28. {{cite web}}: Check date values in: |accessdate= (help); Unknown parameter |accessyear= ignored (|access-date= suggested) (help)
3. ^ :Dunn, Lisa (2005). "Update on SSRL Beam Lines and Techniques". SSRL Headline News. 6 (2): n.p. {{cite journal}}: External link in |title= (help); Unknown parameter |month= ignored (help)