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Scientific Achievements and Contributions

1962–1969 | 1970–1979 | 1980–1989 | 1990–1999 | 2000–-


2009: New Era of Research Begins as World's First Hard X-ray Laser Achieves "First Light"
The world's brightest X-ray source sprang to life at the U.S. Department of Energy's SLAC National Accelerator Laboratory. The Linac Coherent Light Source (LCLS) offers researchers the first-ever glimpse of high-energy or "hard" X-ray laser light produced in a laboratory.
2008: Gamma-ray Large Area Space Telescope Launches into Space
The Gamma-ray Large Area Space Telescope successfully launched into space on June 11, 2008. The satellite, later renamed the Fermi Gamma-ray Space Telescope (FGST), unveils the mysteries of the high-energy universe by studying the most energetic particles of light, observing physical processes far beyond the capabilities of earthbound laboratories. FGST's main instrument, the Large Area Telescope (LAT), operates much like a particle detector. SLAC managed the development of the LAT and integrated the instrument from hardware fabricated at laboratories around the world. SLAC also runs the Instrument Science Operations Center, which processes the LAT data.
2007: New Accelerator Technique Doubles Particle Energy in Just One Meter
Imagine a car that accelerates from zero to 60 in 250 feet and then rockets to 120 miles per hour in just one more inch. That's essentially what a collaboration of accelerator physicists has accomplished, using electrons for their racecars and plasma for the afterburners. Because electrons already travel at near light's speed in an accelerator, the physicists actually doubled the energy of the electrons, not their speed.
2006: First Direct Evidence of Dark Matter
Researchers at the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) observed dark matter, the elusive stuff that makes up a quarter of the universe, in isolation for the first time. KIPAC's Marusa Bradac and her colleagues made the landmark observations by studying a galaxy cluster 3 billion light years away. These observations demonstrate that there are two types of matter: one visible and one invisible. The results also support the theory that the universe contains five times more dark matter than luminous matter.
2006: Nobel Prize Goes to Roger Kornberg
Roger D. Kornberg received the Nobel Prize in Chemistry for being the first to create an actual picture of how transcription works at a molecular level in the important group of organisms called eukaryotes (organisms whose cells have a well-defined nucleus). Kornberg carried out a significant part of the research contributing to this prize at the Stanford Synchrotron Radiation Laboratory (SSRL).
2006: Ground Breaking New Science at SLAC
SLAC officially broke ground for the Linac Coherent Light Source (LCLS), the world's first X-ray free-electron laser. Scheduled for completion in 2009, the LCLS will produce ultra-fast, ultra-short pulses of X-rays a billion times brighter than any other source on earth. The LCLS represents the 4th generation of machines designed to produce synchrotron radiation for scientific studies, an idea originally pioneered at SLAC in the 1970s. Synchrotron radiation, in the form of x-rays or light, is typically produced by electrons circulating in a storage ring 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.
2005: Deciphering the Archimedes Palimpsest
Scientists at SSRL are employing modern technology, including x-ray fluorescence, to completely read the Archimedes Palimpsest, the only source for at least two previously unknown treatises thought out by Archimedes in the 3rd century B.C. A synchrotron x-ray beam has been used to illuminate the obscured work—erased, written over and even painted over in the centuries since its initial creation.
2004: Physicists Discover Dramatic Difference in Behavior of Matter versus Antimatter
The BaBar experiment had demonstrated a dramatic difference in the behavior of matter and antimatter. By sifting through the decays of more than 200 million pairs of B and anti-B mesons, experimenters discovered striking matter-antimatter asymmetry: 910 examples of the B meson decaying to a kaon and a pion, but only 696 examples for the anti-B mesons. While BaBar and other experiments have observed matter-antimatter asymmetries before, this is the first instance in B decays of a difference obtained by simply counting up the number of matter and antimatter decays, a phenomenon known as direct charge parity (CP) violation.
2003: BaBar Identifies New Subatomic Particle
The new particle called the Ds (2317), which combines a charm quark with another heavy quark—an anti strange, has unexpected properties that will provide insight into the force that binds the quarks together. This force, unlike most others in nature, becomes stronger as the distance between the two quarks increases.
2001: BaBar Physicists Find a Striking Difference Between Matter and Antimatter
Physicists from the BaBar experiment directly detected charge-parity violation for the first time in 2001. CP violation is thought to explain why the universe is composed entirely of matter, even though equal amounts of matter and antimatter should have been created in the Big Bang. The result determines directly for the first time the magnitude of the fundamental matter-antimatter asymmetry.


1990s: Experimentation at SLD Reveals Z Boson Preference
The SLD is collecting data on the production of the Z0 boson using a polarized electron beam. This will lead to the most precise measurement of a crucial parameter in particle physics theory as well as unique measurements on B-mesons. Recent running with the SLD has confirmed a predicted small preference for producing the Z0 boson when the beam is polarized with the spins rotating about the beam axis in a left-handed sense. This distinction between left- and right-handedness at the fundamental particle level is one of the most intriguing phenomena in subatomic physics.
1995: Nobel Prize Goes to Martin Perl
SLAC's Martin Perl received the Nobel Prize in Physics for pioneering experimental contributions to lepton physics, specifically for the discovery of the tau lepton. 
1991: SLAC Ignites World Wide Web
The first website in North America is up and running at SLAC in 1991 revealing the potential of the web to particle physicists and the greater community.
1990: Nobel Prize Goes to Richard Taylor
SLAC's Richard Taylor, in conjunction with Jerome Friedman and Henry Kendall, received the Nobel Prize in Physics for pioneering investigations concerning deep inelastic scattering of electrons on protons and bound neutrons, which have been of essential importance for the development of the quark model in particle physics.


1989: SLC Measures the Limit of Three Quark Generations
Completed in 1989, the Stanford Linear Collider (SLC) has been instrumental to particle physics theory. Results gathered in 1989 and 1990 showed that there are only three kinds of neutrinos with a mass less than 1/2 of the Z meson leading to the suggestion that the universe is in fact made up of not more than the three known families of elementary particles, each with two kinds of leptons and two kinds of quarks.
1980-1982: PEP Measures B Meson Lifetime
Operational in 1980, the PEP tunnel, 800 meters in diameter, became home to electron-positron collisions with center-of-mass energies of up to 30 GeV. Measuring the lifetimes of elementary particles, PEP experiments were designed to study how quarks are initially produced in collisions, fragmenting or evolving into various kinds of particles observed in the detection apparatus. In addition PEP has been used to test the theory of Quantum Chromodynamics or QCD, presently believed to describe the strong force that binds quarks together. It was at PEP between 1980–1982 that experimentation revealed the B quark to have a much longer lifetime than previously anticipated.


1976: Nobel Prize Goes to Burton Richter
SLAC's Burton Richter, in conjunction with Samuel Ting, received the Nobel Prize in Physics for pioneering work in the discovery of a heavy elementary particle of a new kind.
1975: The Homebrew Computer Club begins meeting in the SLAC auditorium (1975)
The seminal catalyst of the personal computer revolution ignited the cultural and technological renaissance which transferred computing from corporate/ government hands to the individual.
1975: Discovery of the Tau Lepton at SPEAR
In 1975, using experimental data from 1973–1974, Martin Perl discovered that sometimes when an electron and positron annihilate one another, the detector records only one electron-type track and one muon-type track. These events were noted at rates that could only be explained by postulating a new particle type, one just like the electron only 3,000 times more massive. The resulting discovery of the Tau lepton earned Martin Perl the Nobel Prize in Physics in 1995 for his instrumental contribution to lepton physics.
1973-1974: Charm Discovered at SPEAR
Leading the group that designed and built the Stanford Positron Electron Asymmetric Ring, Burton Richter (SLAC) conducted a series of experiments from 1973–1974 to study the rate of occurrence of events in which a colliding electron and a positron annihilate, disappearing and producing other particles in the process. At certain energies the rate of annihilation seemed inexplicably large. On November 10, 1974, re-measurements in the problematic energy range confirmed a dramatic rate increase whose cause was due to the production of particles containing a new kind of quark, the charm quark. For their work towards the discovery of a new heavy elementary particle, Burton Richter and Samuel Ting (Brookhaven) received the Nobel Prize in Physics in 1976.
1973: SSRL Begins X-ray Imaging
In 1973, SSRL opens as the first laboratory in the world to use synchrotron produced x-rays. More information...


1966-1978: Discovery of the Quark
From 1966–1978, Richard Taylor (SLAC), Henry Kendall (MIT) and Jerome Friedman (MIT) conducted experiments to study how high-energy electrons bounce off protons and neutrons in a target. Their results indicated that there were more electrons bouncing back with high energy at large angles than could be explained if protons and neutrons were uniform spheres of matter. The experiments they conducted came to reveal the extremely small, dense objects moving around within the protons and neutrons known as quarks. For their pioneering work in the development of the quark model of particle physics, these scientists shared the Nobel Prize in Physics in 1990.