or linac
Type of particle accelerator that imparts a series of relatively small increases in energy to subatomic particles as they pass through a sequence of alternating electric fields set up in a linear structure.
The small accelerations add together to give the particles a greater energy than could be achieved by the voltage used in one section alone. One of the world's longest linacs is the 2-mi (3.2-km) machine at the Stanford Linear Accelerator Center, which can accelerate electrons to energies of 50 billion electron volts. Much smaller linacs, both proton and electron types, have important practical applications in medicine and industry.