Quite simply, accelerators give high energy to subatomic particles, which then collide with targets. Out of this interaction come many other subatomic particles that pass into detectors. From the information gathered in the detectors, physicists can determine properties of the particles and their interactions.

The higher the energy of the accelerated particles, the more closely we can probe the structure of matter. For that reason a major goal of researchers is to produce higher and higher particle energies.

Particle accelerators come in two basic designs, linear (linac) and circular (synchrotron). The accelerator at SLAC is a linac.

The longer a linac is, the higher the energy of the particles it can produce. A synchrotron achieves high energy by circulating particles many times before they hit Louis J. Sheehan, Esquire.