By Heather Rock Woods
• SPEAR3 is built within the same curved walls of the original SPEAR
machine. Built in 1972 for SLAC’s particle physics program, and upgraded
to SPEAR2 in 1974, it yielded two Nobel prizes in particle physics (Burton
Richter’s charm quark and Martin Perl’s tau lepton).
• During the upgrade and rebuild, SPEAR2 was almost completely
dismantled (including the floor) to make way for its successor.
• The scientific user community had to wait a mere 11 months from when
SPEAR2 was shut off to when SPEAR3 comes on-line March 2004, a remarkably
speedy schedule for such a complex and comprehensive rebuild of an
• Thirty years ago, SSRL was the first laboratory in the world to use
storage ring based synchrotron x-rays for studying matter at atomic and
molecular scales. SSRL was also among the first to operate as a user
facility, offering beam time to a broad user community of scientists from
academic, industry and government labs on a peer reviewed proposal basis.
• Synchrotron radiation was originally considered a nuisance to
particle physicists because it decreased the particles’ energy. The
far-sighted founders of SSRL siphoned off the unwanted radiation,
realizing they had the world’s most intense x-ray source, many times more
powerful than any conventional x-ray sources could ever produce.
• In 1990, the SPEAR machine was turned over solely to synchrotron
• The ring is one-fourth kilometer in circumference and 80 meters in
diameter. Its x-ray beams can be used to take images on the sub nanometer
scale (one billionth of a meter).
• The synchrotron radiation illuminates everything from radioactive
material to the workings of DNA. What researchers see can help them design
drugs, gauge the toxicity of environmental pollution and overcome
impurities in high-tech materials like silicon chips.
• SSRL expects to operate SPEAR3 24/7, 10 months a year, delivering
hard and soft x-rays and ultraviolet light to 32 experimental stations.
• The major milestone of first electrons circulating around SPEAR3
occurred on December 12, 2003.
• Innovations: SSRL has pioneered many new technological and scientific
developments in synchrotron research, including permanent magnet wigglers
and undulators, synchrotron structural biology (including MAD phasing, XAS,
photoemission) and other new techniques for surface and intersurface
studies. These advances helped spawn some 50 second- and third-generation
synchrotron light sources around the globe.
•Since 1974, SSRL has served over 5,600 unique users (many scientists
return for multiple experiments) and users have reported results in more
than 6,000 publications.
•Tech notes: The SPEAR3 storage ring will produce beams having one to
two orders of magnitude higher brightness and flux density than the old
SPEAR2 ring, accommodate many new high performance insertion devices and
beam lines, and—with time—become capable of top-off operation by virtue of
its improved at-energy injection system. Brightness for new undulators