1947 William Hansen (right) and colleagues with a section of an early linear accelerator that operated at Stanford University in 1947. It was 3.6 meters long and could accelerate electrons to six million electron volts. The world’s newest linear accelerator is the PEP II accelerator at DOE’s SLAC, which will create electron-positron collisions with an energy of ten billion electron volts. Together with the BaBar detector, this collider will be a “factory” for the intensive exploration of the b quark.

PEP II accelerator

BaBar detector