Stanford Synchrotron Radiation Lightsource

Research center at Stanford University

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 (Stanford Positron Electron Asymmetric Ring SPEAR) at nearly the speed of light. The extremely bright light that is produced 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, biology, basic research, and education. 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 San Mateo County, in the city of Menlo Park, California, close to the Stanford University main campus.

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 storage ring. SPEAR had been built in an era of particle colliders, where physicists were more interested in smashing particles together in hope of discovering antimatter than 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 that each used the radiation originating from only one of the large SPEAR dipole (bending) 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. The SLAC 2 mile linear accelerator was the original source for 3GeV electrons, but by 1991 SPEAR had its own 3 section linac and energy ramping booster ring. 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 months each year; the remaining time is used for major maintenance and upgrades where direct access to the storage ring is needed. There are currently 17 beamlines and over 30 unique experimental stations which are made available to users from universities, government labs, and industry from all over the world.