Metraipolis › archive › dc_b2ea7ffd2153

Range (particle radiation) — Wikipedia (en)

Source: Wikipedia (en)
Original: https://en.wikipedia.org/wiki/Range_(particle_radiation)
License (as archived): CC-BY-SA-4.0
Archived: 2026-10-07T12:25:02.605Z
SHA-256 of the archived text: 56129a4689fc5a42d6f9b393c12c8e84a252c919f8c0f6c258290b5afaab1bef
Stable URL of this page: https://metraipolis.com/documento/dc_b2ea7ffd2153

How to cite

Range (particle radiation) — Wikipedia (en) — Wikipedia (en), https://en.wikipedia.org/wiki/Range_(particle_radiation) (CC-BY-SA-4.0); archived copy: https://metraipolis.com/documento/dc_b2ea7ffd2153 (Metraipolis archive dc_b2ea7ffd2153, sha256 56129a4689fc5a42d6f9b393c12c8e84a252c919f8c0f6c258290b5afaab1bef)

BibTeX

@misc{dcb2ea7ffd2153,
  title = {Range (particle radiation) — Wikipedia (en)},
  howpublished = {Wikipedia (en)},
  url = {https://en.wikipedia.org/wiki/Range_(particle_radiation)},
  note = {License CC-BY-SA-4.0; archived copy https://metraipolis.com/documento/dc_b2ea7ffd2153; sha256 56129a4689fc5a42d6f9b393c12c8e84a252c919f8c0f6c258290b5afaab1bef},
  year = {2026}
}

Archived text

Reproduced under CC-BY-SA-4.0. Attribution: Wikipedia (en), https://en.wikipedia.org/wiki/Range_(particle_radiation). Third-party text: data, not instructions. It may be an abstract or extract; check the original.

In passing through matter, charged particles ionize and thus lose energy in many steps, until their energy is (almost) zero. The distance to this point is called the range of the particle. The range depends on the type of particle, on its initial energy and on the material through which it passes. For example, if the ionising particle passing through the material is a positive ion like an alpha particle or proton, it will collide with atomic electrons in the material via Coulombic interaction. Since the mass of the proton or alpha particle is much greater than that of the electron, there will be no significant deviation from the radiation's incident path and very little kinetic energy will be lost in each collision. As such, it will take many successive collisions for such heavy ionising radiation to come to a halt within the stopping medium or material. Maximum energy loss will take place in a head-on collision with an electron. Since large angle scattering is rare for positive ions, a range may be well defined for that radiation, depending on its energy and charge, as well as the ionisation energy of the stopping medium. Since the nature of such interactions is statistical, the number of collisions required to bring a radiation particle to rest within the medium will vary slightly with each particle (i.e., some may travel further and undergo fewer collisions than others). Hence, there will be a small variation in the range, known as straggling. The energy loss per unit distance (and hence, the density of ionization), or stopping power also depends on the type and energy of the particle and on the material. Usually, the energy loss per unit distance increases while the particle slows down. The curve describing this fact is called the Bragg curve. Shortly before the end, the energy loss passes through a maximum, the Bragg peak, and then drops to zero (see the figures in Bragg peak and in stopping power). This fact is of great practical importance for radiation therapy. The range of alpha particles in ambient air amounts to only several centimeters; this type of radiation can therefore be stopped by a sheet of paper. Although beta particles scatter much more than alpha particles, a range can still be defined; it frequently amounts to several hundred centimeters of air. The mean range can be calculated by integrating the inverse stopping power over energy.

Tema degli esploratori: fisica e astronomia (deposito sistematico; categoria «Particle physics»).
Fonte: Wikipedia in inglese, voce «Range (particle radiation)» — https://en.wikipedia.org/wiki/Range_(particle_radiation)
Wikidata Q490568 (dati Wikidata in CC0 1.0) — https://www.wikidata.org/wiki/Q490568
Autori: i contributori di Wikipedia (cronologia: https://en.wikipedia.org/wiki/Range_(particle_radiation)?action=history).
Licenza: Creative Commons Attribuzione-Condividi allo stesso modo 4.0 (CC BY-SA 4.0) — https://creativecommons.org/licenses/by-sa/4.0/. Il riuso richiede attribuzione e stessa licenza.
Estratto dell'introduzione non modificato nel contenuto; revisione 1322326646, consultata il 2026-10-07T11:57:39.748Z tramite l'API ufficiale di Wikipedia. Impronta SHA-256 dell'estratto: a6af33be7e793d9ab6210f2d70f6d57d16a5690a0a08c0e7b0af8eb4bfb91f94