South Linear Accelerator
The South Linear Accelerator is one of the two long, straight sections of Jefferson Lab's accelerator. Electrons gain energy in this section by passing through acceleration cavities. There are 160 cavities in this straightaway, all lined up end to end. That's enough cavities to increase an electron's energy by 400 million volts each time it passes through this section. Electrons can pass though this section as many as five times! The cavities are powered by microwaves that travel down the skinny rectangular pipes from the service buildings above ground.
Since the cavities won't work right unless they are kept very cold, they are bathed in Liquid Helium from the Central Helium Liquefier inside large tanks called cryomodules. Each of the 20 cryomodules in the South LINAC is a large thermos bottle that was put together in the Test Lab.