Editing Elastic scattering

{{Short description|Particle collisions conserving kinetic energy}}
{{More sources needed|date=December 2009}}

'''Elastic scattering''' is a form of particle [[scattering]] in [[scattering theory]], [[nuclear physics]] and [[particle physics]]. In this process, the internal states of the [[Elementary particle|particle]]s involved stay the same. In the non-relativistic case, where the relative velocities of the particles are much less than the [[speed of light]], elastic scattering simply means that the total [[kinetic energy]] of the system is conserved.<ref>“Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) for materials characterization,” B.J. Inkson, “Materials Characterization Using Nondestructive Evaluation (NDE) Methods,” 2016. https://www.sciencedirect.com/topics/chemistry/elastic-scattering</ref> At relativistic velocities, elastic scattering also requires the final state to have the same number of particles as the initial state and for them to be of the same kind.<ref>{{cite book|title=Fields|author=Warren Siegel|author-link=Warren Siegel|pages=362|url=https://arxiv.org/abs/hep-th/9912205|year=1999|accessdate=2024-04-30}}</ref>

==Rutherford scattering==
When the incident particle, such as an [[alpha particle]] or [[electron]], is [[diffraction|diffracted]] in the [[Coulomb potential]] of [[atom]]s and [[molecule]]s, the elastic scattering process is called [[Rutherford scattering]]. In many [[electron]] diffraction techniques like reflection high energy electron diffraction ([[RHEED]]), transmission electron diffraction (TED), and gas electron diffraction (GED), where the incident electrons have sufficiently high energy (>10 keV), the elastic [[electron scattering]] becomes the main component of the scattering process and the scattering intensity is expressed as a function of the [[momentum transfer]] defined as the difference between the momentum vector of the incident electron and that of the scattered electron.

==Optical elastic scattering==
* In [[Thomson scattering]] light interacts with electrons (this is the low-energy limit of [[Compton scattering]]).<ref>Froula, Dustin H. Plasma scattering of electromagnetic radiation. Academic Press is an imprint of Elsevier, 2011.</ref>
* In [[Rayleigh scattering]] a medium composed of particles whose sizes are much smaller than the [[wavelength]] scatters light sideways. In this scattering process, the energy (and therefore the wavelength) of the incident light is conserved and only its direction is changed. In this case, the scattering intensity is inversely proportional to the fourth power of the reciprocal wavelength of the light.<ref>Young, Andrew T. [https://www.researchgate.net/profile/Hans-Moosmuller/post/Does-Rayleigh-Scattering-really-explain-blueness-of-sky/attachment/59d6338dc49f478072ea23ef/AS%3A273644943544335%401442253446960/download/Young1982PhysicsToday.pdf "Rayleigh scattering."] Phys. Today 35.1 (1982): 42-48.</ref>{{rp|2}}

==Nuclear particle physics==
For particles with the mass of a proton or greater, elastic scattering is one of the main methods by which the particles interact with matter. At relativistic energies, protons, neutrons, [[helium]] ions, and [[HZE ions]] will undergo numerous elastic collisions before they are dissipated. This is a major concern with many types of [[ionizing radiation]], including [[galactic cosmic rays]], [[solar proton event]]s, free neutrons in [[nuclear weapon]] design and [[nuclear reactor]] design, spaceship design, and the study of the [[Earth's magnetic field]]. In designing an effective [[biological shield]], proper attention must be made to the [[linear energy transfer]] of the particles as they propagate through the shield. In nuclear reactors, the neutron's [[mean free path]] is critical as it undergoes elastic scattering on its way to becoming a slow-moving [[thermal neutron]].

Besides elastic scattering, charged particles also undergo effects from their [[elementary charge]], which repels them away from nuclei and causes their path to be curved inside an [[electric field]]. Particles can also undergo [[inelastic scattering]] and capture due to nuclear reactions. Protons and neutrons do this more often than heavier particles. Neutrons are also capable of causing [[Nuclear fission|fission]] in an incident nucleus. Light nuclei like [[deuterium]] and [[lithium]] can combine in [[nuclear fusion]].

==See also==
* [[Elastic collision]]
* [[Inelastic scattering]]
* [[Scattering theory]]
* [[Thomson scattering]]

==References==
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[[Category:Particle physics]]
[[Category:Scattering]]