Stanford Synchrotron Radiation Laboratory
Encyclopedia
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.
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. It is located in southern San Mateo County
, just outside the city of Menlo Park
.
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 collider
s, where physicists were more interested in smashing particles together in hope of discovering antimatter
then in using x-ray radiation for solid state physics and chemistry. From those meager beginnings the Stanford Synchrotron
Radiation Project (SSRP) began. 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 Lightsource as part of the SLAC
National Accelerator Laboratory facility. SSRL currently operates 24/7 for about nine solid months out of the year; the remaining time is used for major maintenance and upgrades where direct access to the storage ring is needed. There are over 30 unique experimental stations which are made available to users from universities, government labs, and industry from all over the world.
and Station
SLAC National Accelerator Laboratory
The SLAC National Accelerator Laboratory, originally named Stanford Linear Accelerator Center, is a United States Department of Energy National Laboratory operated by Stanford University under the programmatic direction of the U.S...
, is operated by Stanford University
Stanford University
The Leland Stanford Junior University, commonly referred to as Stanford University or Stanford, is a private research university on an campus located near Palo Alto, California. It is situated in the northwestern Santa Clara Valley on the San Francisco Peninsula, approximately northwest of San...
for the Department of Energy
United States Department of Energy
The United States Department of Energy is a Cabinet-level department of the United States government concerned with the United States' policies regarding energy and safety in handling nuclear material...
. SSRL is a National User Facility which provides synchrotron
Synchrotron
A synchrotron is a particular type of cyclic particle accelerator in which the magnetic field and the electric field are carefully synchronised with the travelling particle beam. The proton synchrotron was originally conceived by Sir Marcus Oliphant...
radiation, a name given to electromagnetic radiation in the x-ray, ultraviolet, visible and infrared realms produced by electrons circulating in a storage ring
Storage ring
A storage ring is a type of circular particle accelerator in which a continuous or pulsed particle beam may be kept circulating for a long period of time, up to many hours. Storage of a particular particle depends upon the mass, energy and usually charge of the particle being stored...
(SPEAR
SPEAR
SPEAR was a collider at the SLAC National Accelerator Laboratory. It began running in 1972, colliding electrons and positrons with an energy of...
) 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.
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. It is located in southern San Mateo County
San Mateo County, California
San Mateo County is a county located in the San Francisco Bay Area of the U.S. state of California. It covers most of the San Francisco Peninsula just south of San Francisco, and north of Santa Clara County. San Francisco International Airport is located at the northern end of the county, and...
, just outside the city of Menlo Park
Menlo Park, California
Menlo Park, California is a city at the eastern edge of San Mateo County, in the San Francisco Bay Area of California, in the United States. It is bordered by San Francisco Bay on the north and east; East Palo Alto, Palo Alto, and Stanford to the south; Atherton, North Fair Oaks, and Redwood City...
.
History
In 1972 the first x-rayX-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...
beamline
Beamline
In particle physics, a beamline is the line in a linear accelerator along which a beam of particles travels. It may also refer to the line of travel within a bending section such as a storage ring or cyclotron, or an external beam extracted from a cyclic accelerator.In materials science, physics,...
was constructed by Ingolf Lindau and Piero Pianetta as literally a "hole in the wall" extending off of the SPEAR (Stanford Positron
Positron
The positron or antielectron is the antiparticle or the antimatter counterpart of the electron. The positron has an electric charge of +1e, a spin of ½, and has the same mass as an electron...
Electron
Electron
The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...
Asymmetric Ring) storage ring. At that time, the SPEAR had been built in an era of particle collider
Collider
A collider is a type of a particle accelerator involving directed beams of particles.Colliders may either be ring accelerators or linear accelerators.-Explanation:...
s, where physicists were more interested in smashing particles together in hope of discovering antimatter
Antimatter
In particle physics, antimatter is the extension of the concept of the antiparticle to matter, where antimatter is composed of antiparticles in the same way that normal matter is composed of particles...
then in using x-ray radiation for solid state physics and chemistry. From those meager beginnings the Stanford Synchrotron
Synchrotron
A synchrotron is a particular type of cyclic particle accelerator in which the magnetic field and the electric field are carefully synchronised with the travelling particle beam. The proton synchrotron was originally conceived by Sir Marcus Oliphant...
Radiation Project (SSRP) began. 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
Monochromator
A monochromator is an optical device that transmits a mechanically selectable narrow band of wavelengths of light or other radiation chosen from a wider range of wavelengths available at the input...
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
Synchrotron radiation
The electromagnetic radiation emitted when charged particles are accelerated radially is called synchrotron radiation. It is produced in synchrotrons using bending magnets, undulators and/or wigglers...
. Today the SPEAR storage ring is dedicated completely to the Stanford Synchrotron Radiation Lightsource as part of the SLAC
SLAC National Accelerator Laboratory
The SLAC National Accelerator Laboratory, originally named Stanford Linear Accelerator Center, is a United States Department of Energy National Laboratory operated by Stanford University under the programmatic direction of the U.S...
National Accelerator Laboratory facility. SSRL currently operates 24/7 for about nine solid months out of the year; the remaining time is used for major maintenance and upgrades where direct access to the storage ring is needed. There are over 30 unique experimental stations which are made available to users from universities, government labs, and industry from all over the world.
Directors
- Sebastian DoniachSebastian DoniachSebastian Doniach is a British-American physicist and professor at Stanford University. His research interests include theoretical condensed matter physics, superconductivity, and biophysics....
1973-1977 - Arthur Bienenstock 1978-1998
- Keith HodgsonKeith HodgsonKeith O. Hodgson is a Professor of Chemistry at Stanford university and the Stanford Synchrotron Radiation Lightsource. He received his B.S. in 1969 from the University of Virginia and his Ph.D. in 1972 from University of California at Berkeley....
1998-2005 - Joachim StöhrJoachim StöhrJoachim Stöhr received his Ph.D. in Physics from the Technical University of Munich. After postdoctoral work at Lawrence Berkeley National Laboratory he worked as a staff scientist at the Stanford Synchrotron Radiation Laboratory and at EXXON Corporate Research Laboratory...
2005-2009 - Piero Pianetta 2009
- Chi-Chang Kao (Acting Director) 2010-
Facilities
listed by BeamlineBeamline
In particle physics, a beamline is the line in a linear accelerator along which a beam of particles travels. It may also refer to the line of travel within a bending section such as a storage ring or cyclotron, or an external beam extracted from a cyclic accelerator.In materials science, physics,...
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 scatteringResonant inelastic X-ray scatteringResonant Inelastic X-ray Scattering is an x-ray spectroscopy technique used to investigate the electronic structure of molecules and materials....
). - 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-edgeLigand K-edgeLigand K-edge XAS is a spectroscopic technique that allows the direct study of metal-ligand bonding. In a XAS experiment, electrons in ligand 1s orbitals are excited to unfilled p Ligand K-edge XAS is a spectroscopic technique that allows the direct study of metal-ligand bonding. In a XAS...
(carbonCarbonCarbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
, nitrogenNitrogenNitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
, oxygenOxygenOxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
, chlorineChlorineChlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
), PES (Photoemission spectroscopyPhotoemission spectroscopyPhotoemission spectroscopy , also known as photoelectron spectroscopy, refers to energy measurement of electrons emitted from solids, gases or liquids by the photoelectric effect, in order to determine the binding energies of electrons in a substance...
), and L-edgeMetal L-edgeMetal L-edge XAS is an experimental technique that involves the excitation of a metal 2p electron to unfilled metal d orbitals...
measurements. All experiments on these beamlines require special handling and advanced ultra high vacuumUltra high vacuumUltra-high vacuum is the vacuum regime characterised by pressures lower than about 10−7 pascal or 100 nanopascals . UHV requires the use of unusual materials in construction and by heating the entire system to 180°C for several hours to remove water and other trace gases which adsorb on the...
experience and techniques. - BL 11-3 Materials ScienceMaterials scienceMaterials science is an interdisciplinary field applying the properties of matter to various areas of science and engineering. This scientific field investigates the relationship between the structure of materials at atomic or molecular scales and their macroscopic properties. It incorporates...
Scattering, Reflectivity and Single CrystalSingle crystalA single crystal or monocrystalline solid is a material in which the crystal lattice of the entire sample is continuous and unbroken to the edges of the sample, with no grain boundaries...
DiffractionDiffractionDiffraction refers to various phenomena which occur when a wave encounters an obstacle. Italian scientist Francesco Maria Grimaldi coined the word "diffraction" and was the first to record accurate observations of the phenomenon in 1665...
Experiments. Uses to date include: study of structure in organic, metal, and semiconductorSemiconductorA semiconductor is a material with electrical conductivity due to electron flow intermediate in magnitude between that of a conductor and an insulator. This means a conductivity roughly in the range of 103 to 10−8 siemens per centimeter...
thin films and multilayers; study of charge-density waves in rare earthRare earth elementAs defined by IUPAC, rare earth elements or rare earth metals are a set of seventeen chemical elements in the periodic table, specifically the fifteen lanthanides plus scandium and yttrium...
tri-tellurides; study of in-situ growth of biogenic minerals; partial determination of texture in recrystallized pumicePumicePumice is a textural term for a volcanic rock that is a solidified frothy lava typically created when super-heated, highly pressurized rock is violently ejected from a volcano. It can be formed when lava and water are mixed. This unusual formation is due to the simultaneous actions of rapid...
; quick determination of single crystal orientation. - 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)