ABSTRACT
Experimental information in high-energy physics has historically most “commonly” been obtained from accelerators: machines that accelerate charged particles to very high speeds and then let them collide with other particles. They are very expensive to build and maintain, and they have a limited use in terms of the fundamental physics that they can reveal. Accelerators have played an essential role in particle physics. Without them it would simply not be possible to check in any detailed way whether or not our theories were correct. Accelerators have grown out of their core purpose of providing experimental information for particle physics, and today are used in condensed matter physics, biomedical technologies, geophysics, electronics, food processing, and many other areas. Particle beams in general do not consist of streams of charged particles.
