Cut-away Section of Stanford Linear Electron Accelerator

Starting in 1947, physicists at Stanford University worked to develop a particular type of particle accelerator, or “atom smasher,” that would send electrons down a long, straight tube, feeding energy to them by means of an electric wave traveling along the tube. By the early 1960s their project had become a national laboratory, supported by Federal Government funding of $100,000,000.
This is a small section of the two-mile long SLAC, cut away to show the carefully placed diaphragms that slow the traveling electric field to the proper speed, and also one of the waveguide connections through which electromagnetic energy was fed into the accelerator.
SLAC National Accelerator Laboratory in Menlo Park, California is home to a two-mile (3.2 km) long linear particle accelerator, currently the longest in the world. Construction of the SLAC site commenced in 1962, and the linear accelerator (linac) began operation for physics experiments in 1966. For information on the laboratory, see
A linac is a type of particle accelerator that is used to greatly increase the velocity of charged subatomic particles or ions by subjecting the particles to a series of oscillating electric potentials along the length of a linear beamline. Linacs have many applications, including providing beams for collision with stationary targets for physics experiments, and serving as the particle injectors for ring-shaped accelerators and storage rings (e.g., synchrotrons and colliders). Linacs also provide the particle beams that are used directly or indirectly in radiation therapy and in the production of medical isotopes.
The SLAC linac has been used to generate high-energy electron and positron beams for particle physics experiments and to provide the electron beams for SLAC's Stanford Synchrotron Radiation Lightsource (SSRL). Experiments conducted at SLAC from 1966 to date have led to six Nobel prizes, five in physics and one in chemistry. For an historical timeline of major events at SLAC, see
Today the SLAC linac provides the electron beams to create a unique source of X-ray laser pulses for investigating matter at the smallest and fastest scales at the laboratory's Linac Coherent Light Source (LCLS).
The SLAC linac uses 2 miles of copper cavities into which radiofrequency (rf) waves are fed to accelerate the particle bunches. The electrically isolated cylindrical cavities are enclosed within a hollow vacuum chamber. Klystrons, specialized linear-beam amplifier tubes, are used to generate the rf power. External waveguides couple the microwave energy from the klystrons into and out of the cavities.
Object N-09538 is a section of the SLAC linac beamtube with its attached waveguide for the input of rf power. The beamtube is cutaway to show the individual cavities within this section.
Object Name
linear accelerator, SLAC, cut-away
date made
Bishop, Philip W.
Sanders, Jack
Physical Description
copper (overall material)
stainless steel (flanges (2) material)
overall: 9 in x 10 1/16 in x 6 1/4 in; 22.86 cm x 25.55875 cm x 15.875 cm
extension of waveguide flange beyond end of beam tube flange: 1 1/16 in; 2.69875 cm
length of beam tube along axis: 9 in; 22.86 cm
rim of beam tube flange to end of waveguide flange: 2 3/4 in; 6.985 cm
external diam. of beam tube: 4 in; 10.16 cm
internal diam. diam. of beam tube: 3 7/32 in; 8.17563 cm
internal length of cavity: 1 1/8 in; 2.8575 cm
thickness of diaphragm: 7/32 in; .55562 cm
diam. of aperture: 25/32 in; 1.98438 cm
diam. of waveguide flange: 4 31/32 in; 12.62062 cm
rectangular waveguide channel: 2 27/32 in x 1 11/32 in; 7.22313 cm x 3.41313 cm
place made
United States: California, Stanford
ID Number
catalog number
accession number
Science & Mathematics
Modern Physics
Science & Scientific Instruments
See more items in
Medicine and Science: Modern Physics
The Early Sixties: American Science
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of Stanford University
Additional Media

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