# Charged particle beam

(Redirected from Charged-particle beam)

A charged particle beam is a spatially localized group of electrically charged particles that have approximately the same position, kinetic energy (resulting in the same velocity), and direction. The kinetic energies of the particles are much larger than the energies of particles at ambient temperature. The high energy and directionality of charged particle beams make them useful for applications (see Particle Beam Usage and Electron beam technology).

Such beams can be split into two main classes:

1. unbunched beams (coasting beams[1] or DC beams), which have no longitudinal substructure in the direction of beam motion.
2. bunched beams, in which the particles are distributed into pulses (bunches) of particles. Bunched beams are most common in modern facilities, since the most modern accelerator concepts require bunched beams for acceleration.[2]

Assuming a normal distribution of particle positions and impulses, a charged particle beam (or a bunch of the beam) is characterized by[3]

These parameters can be expressed in various ways. For example, the current and beam size can be combined into the current density, and the current and energy (or beam voltage V) can be combined into the perveance K = I V−3/2.

The charged particle beams that can be manipulated in particle accelerators can be subdivided into electron beams, ion beams and proton beams.

## References

1. ^ Ruggiero, F; Thomashausen, J (June 2005), CERN Accelerator School: Basic Course On General Accelerator Physics, p. 296, doi:10.5170/CERN-2005-004, CERN-2005-004, retrieved 2017-11-14
2. ^ Edwards, D.A.; Syphers, M.J. (1993). An Introduction to the Physics of High Energy Accelerators. Weinheim, Germany: Wiley-VCH. ISBN 9780471551638.
3. ^ Humphries, Stanley (1990). Charged particle beams (PDF). New York: Wiley-Interscience. ISBN 9780471600145.