Producer's Notes: Homegrown Particle Accelerators

If you’re enthralled by the Large Hadron Collider, you’ll want to watch QUEST’s story on atom smashers.

QUEST journeys back in time to find out how physicists on the UC Berkeley campus in the 1930s, and at the Stanford Linear Accelerator Center in Menlo Park in the 1970s, created so-called “atom smashers” that led to key discoveries about the tiny constituents of the atom – from the nucleus all the way down to the quarks.

These homegrown particle accelerators paved the way for the Large Hadron Collider, so big that its 17-mile underground tunnel straddles the border between Switzerland and France.

Our 12-minute television story starts with the building of the cyclotron, a particle accelerator that UC Berkeley physicist Ernest Lawrence conceived of in 1930. Its first iteration fit in the palm of his hand. It was a breakthrough because without requiring much energy, it could produce very energetic particles in a small space. This allowed physicists to readily investigate the atom’s nucleus by creating elements with large nuclei.

The resulting new field of nuclear science has a complicated legacy, of course. It was used to build the atomic bomb, as well as to create the medical accelerators that are now commonly used to fight cancer.

Subsequent versions of the cyclotron were so big that they were housed in their own buildings. For our TV story, we filmed at the 88-inch cyclotron at the Lawrence Berkeley National Laboratory. The Berkeley Lab, as it’s referred to, was the laboratory that Lawrence built above the UC Berkeley campus to house his ever-bigger cyclotrons.

Ernest Lawrence above the 184-inch cyclotron. This was the biggest cyclotron he built at his laboratory in Berkeley, which later was named the Lawrence Berkeley National Laboratory. The 184-inch cyclotron no longer exists. But the building houses the Advanced Light Source, which uses the X-rays produced by a particle accelerator to create detailed images of everything from biological samples to building materials.

The 88-inch cyclotron was built in 1961, three years after Lawrence died, and is very much an active research tool. Physicists are still using it to create elements with big nuclei. But about 40 percent of the cyclotron’s time is dedicated to something completely different. It is one of only two facilities in California where you can test the computer chips that go into satellites, by exposing them to high-radiation conditions similar to what they encounter in space. In our story, we follow this testing process.

We also tell part of the history of the Stanford Linear Accelerator Center, now called the SLAC National Accelerator Laboratory. What was then the longest particle accelerator in the world began to operate in Menlo Park in 1966. This linear accelerator sent electron beams traveling down a two-mile row of microwave-oven-like devices and smashed them against a stationary target. Physicists used these accelerated electrons to investigate what was inside the protons and neutrons, and in 1968 they found that they were made up of minuscule constituents they called quarks.

A few years later, SLAC physicist Burton Richter built a collider, a type of particle accelerator in which particle beams are smashed against each other to reach high energy levels. The so-called SPEAR collider that Richter built led him and his team to discover a more massive quark called the charm quark. This breakthrough helped physicists come up with our current understanding of how matter is organized, a theory called the Standard Model of particle physics.

Today, dozens of physicists and graduate students at the Berkeley Lab and SLAC are working on the Large Hadron Collider, making regular trips to Geneva and crunching data back home in their labs in hopes of making discoveries that will answer some of the questions that the Standard Model now leaves unanswered. For example, what is the invisible “dark matter” that makes up 25 percent of the universe?

Both at SLAC and at the Berkeley Lab, particle accelerators are being used for exciting new work. The X-rays emitted by accelerated particles, which were at first considered a nuisance, were quickly harnessed in the 1970s to make detailed images. This synchrotron radiation is now used to understand everything from the structure of proteins that could lead to drug development, to materials that could one day be used to build faster computers, and fossils that help prove Darwin’s theory of evolution.