traveling-wave linear accelerator

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Stanford Linear Accelerator Center, Menlo Park, California

Figure 4: Waveguide acceleration chamber of a linear electron accelerator showing the irises, which decrease the phase velocity of the wave (see text).

traveling-wave linear accelerator

Also known as: electron linac, linear electron accelerator

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July 14, 2026

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Stanford Linear Accelerator Center, Menlo Park, California — Stanford Linear Accelerator Center, Menlo Park, California The Stanford Linear Accelerator Center, Menlo Park, California, has a 3.2-kilometre (2-mile) linear electron accelerator, the longest linear accelerator in the world.

A traveling-wave linear accelerator is a type of particle accelerator that uses a sequence of alternating electric fields to gradually increase the energy of subatomic particles, such as electrons. Unlike standing-wave accelerators used for heavier particles, electron linacs employ traveling waves.12

Electrons, due to their low mass, quickly approach the speed of light. In a traveling-wave linac, the accelerating electromagnetic wave moves at the speed of light, allowing the electrons to effectively "ride the crest" of the wave and continuously experience acceleration. The acceleration chamber is a pipe that guides the electromagnetic wave, which is slowed down by metal irises to match the electron's speed. These accelerators are used in applications like radiography, cancer treatment, and as injectors for other particle accelerators.12

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particle accelerator
Linear electron accelerators
The force that acts on electrons in a traveling-wave accelerator is provided by an electromagnetic field with a frequency near 3,000 MHz (1 MHz = 1,000,000 Hertz, or 1,000,000 cycles per second)—a microwave. The acceleration chamber is an evacuated cylindrical pipe that…
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The force that acts on electrons in a traveling-wave accelerator is provided by an electromagnetic field with a frequency near 3,000 MHz (1 MHz = 1,000,000 Hertz, or 1,000,000 cycles per second)—a microwave. The acceleration chamber is an evacuated cylindrical pipe that…
Read More

particle accelerator
History
…in California, constructed the first traveling-wave linear accelerator of electrons, exploiting microwave technology that had been developed for radar during World War II.
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…in California, constructed the first traveling-wave linear accelerator of electrons, exploiting microwave technology that had been developed for radar during World War II.
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linear accelerator
Electron linacs utilize traveling waves rather than standing waves. Because of their small mass, electrons travel at close to the speed of light at energies as low as 5 megaelectron volts. They can therefore travel along the linac with the accelerating wave, in effect riding…
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Electron linacs utilize traveling waves rather than standing waves. Because of their small mass, electrons travel at close to the speed of light at energies as low as 5 megaelectron volts. They can therefore travel along the linac with the accelerating wave, in effect riding…
Read More

spectroscopy
Synchrotron sources
…synchrotron source consists of a linear electron accelerator that injects high-energy electrons into a storage ring (see particle accelerator: Synchrotrons). Since the intensity of the synchrotron radiation is proportional to the circulating current, many electron pulses from the injecting accelerator are packed into a single high-current bunch of electrons, and…
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…synchrotron source consists of a linear electron accelerator that injects high-energy electrons into a storage ring (see particle accelerator: Synchrotrons). Since the intensity of the synchrotron radiation is proportional to the circulating current, many electron pulses from the injecting accelerator are packed into a single high-current bunch of electrons, and…
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Robert Hofstadter
At Stanford he used a linear electron accelerator to measure and explore the constituents of atomic nuclei. At the time, protons, neutrons, and electrons were all thought to be structureless particles; Hofstadter discovered that protons and neutrons have a definite size and form. He was able to determine the precise…
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At Stanford he used a linear electron accelerator to measure and explore the constituents of atomic nuclei. At the time, protons, neutrons, and electrons were all thought to be structureless particles; Hofstadter discovered that protons and neutrons have a definite size and form. He was able to determine the precise…
Read More