ASME-Landmark:Stanford Linear Accelerator Center

The Stanford Linear Accelerator Center—renamed in 2009 to the SLAC National Accelerator Laboratory—is, at two miles, the longest in the world.

The main accelerator is buried 30 feet (10 meters) underground and passes underneath Interstate Highway 280. Built in 1962, the engineering problems facing the accelerator's design included manufacturing a thousand sections of precision copper waveguide, aligning these sections over a two-mile length, producing high-power pulsed microwaves, and safely handling the intense high-energy beam of electrons.

The accelerating waveguide, which is basically a long conducting tube about four inches in diameter, was assembled from cylinders and disks that formed nearly 100,000 individual microwave cavities, made of high-purity copper, which were machined to a precision of about two ten-thousandths of an inch and then brazed in a hydrogen furnace into ten-foot-long sections. Each cavity was then 'tuned' by slightly deforming the outside using hydraulic rams. This operation required new techniques for mass production to very high standards.

The linear accelerator accelerates electrons to the very high energy needed in the study of subatomic particles and forces. Experiments performed here have shown that the proton, one of the building blocks of the atom, is in turn composed of smaller particles now called quarks. Other research here has uncovered new families of particles and demonstrated subtle effects of the weak nuclear force. This research requires the utmost precision in the large and unique electromechanical devices and systems that accelerate, define, deliver, and store the beams of particles and in the detectors that analyze the results of the particle of interactions. See ASME website for more information