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Topic: Compton scattering


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In the News (Wed 19 Jun 19)

  
  Compton scattering - Wikipedia, the free encyclopedia
Compton scattering is of prime importance to radiobiology, as it happens to be the most probable interaction of high energy X rays with atomic nuclei in living beings and is applied in radiation therapy.
Compton scattering has on occasion been proposed as an alternative explanation for the phenomenon of the redshift by opponents of the Big Bang theory, although this is not generally accepted because the influence of the Compton scattering would be noticeable in the spectral lines of distant objects and this is not observed.
Compton Scatter is an important effect in Gamma spectroscopy, as it is possible for the gamma rays to scatter out of the detectors used.
en.wikipedia.org /wiki/Compton_scattering   (636 words)

  
 Scattering - Wikipedia, the free encyclopedia
Scattering is a general physical process whereby some form of radiation, such as light, sound, or moving particles, is forced to deviate from a straight trajectory by one or more localized non-uniformities in the medium through which it passes.
Rayleigh scattering is a process in which electromagnetic radiation (including light) is scattered by a small spherical volume of variant refractive index, such as a particle, bubble, droplet, or even a density fluctuation.
In scattering experiments, a target of some material is bombarded with a beam of particles (typically electrons, protons, or neutrons) and the number of particles emerging in various directions is measured.
en.wikipedia.org /wiki/Scattering   (2401 words)

  
 Compton Scattering   (Site not responding. Last check: 2007-09-11)
Arthur H. Compton observed the scattering of x-rays from electrons in a carbon target and found scattered x-rays with a longer wavelength than those incident upon the target.
Compton explained and modeled the data by assuming a particle (photon) nature for light and applying conservation of energy and conservation of momentum to the collision between the photon and the electron.
Compton was awarded the Nobel Prize in 1927 for the "discovery of the effect named after him".
hyperphysics.phy-astr.gsu.edu /hbase/quantum/comptint.html   (139 words)

  
 Compton Scattering
Compton scattering occurs when a photon "hits" an electron with some of the photon energy being transferred to the charged particle.
It is possible, however, to determine the angle of incidence the cosmic photon made with respect to this line because the Compton scattering law provides for a definite relationship between this angle and the energy of the scattered photon (measured in the second level) and the scattering electron (measured in the first level).
Compton scatter telescopes have wide fields-of-view and can form images even though the so-called point spread function (the probability that an event came from a certain area on the sky) is a ring.
imagine.gsfc.nasa.gov /docs/science/how_l2/compton_scatter.html   (621 words)

  
 NEEP Lab
The Compton Scattering lab aims to expose students to the Compton scattering effect, demonstrate how to measure the effect at different angles and how this affects the scattering cross section, show the energy-angle interdependence of the effect, and show the differences between observed data and theoretical calculations.
This beam of gamma radiation is then used to strike a scatterer at varying angles, with the scattering energy being measured by the detector and analyzed as a function of scattering angle.
Scattering measurements are made at 10 degree increments for between 110 degrees and 160 degrees and between 0 degrees and 70 degrees.
www.rpi.edu /~danony/NEEP/compton1.htm   (247 words)

  
 The Kinematics and Dynamics of Compton Scattering
Compton or incoherent scattering is the scattering of photons from free electrons.
In the energy region of interest, incoherent scattering may be treated as the elastic scattering of a photon from a free electron that is initially at rest.
as an indication of the forward-biased anisotropy of Compton scattering.
www.mathcad.com /Library/LibraryContent/MathML/compton.htm   (1425 words)

  
 Oilfield Glossary: Term 'Compton scattering'
Compton scattering occurs with high probability at intermediate gamma ray energies, between 75 keV and 10 MeV in sedimentary formations.
When a beam of gamma rays traverses a material, the total reduction due to Compton scattering depends on the electron density of the material?the higher the density, the larger the reduction.
Compton scattering is also an important mechanism in gamma ray detectors.
www.glossary.oilfield.slb.com /Display.cfm?Term=Compton+scattering   (121 words)

  
 Compton Scattering   (Site not responding. Last check: 2007-09-11)
Compton Scattering, also known as incoherent scattering, occurs when the incident x-ray photon ejects a electron from an atom and an x-ray photon of lower energy is scattered from the atom.
Theta is the scattering angle of the scattered photon.
Theta is the angle between the scattered photon direction and the path of the incident photon.
www.ndt-ed.org /EducationResources/CommunityCollege/Radiography/Physics/comptonscattering.htm   (381 words)

  
 Photoelectrons, Compton and Inverse Compton Scattering
To show this, Compton scattered x-ray radiation off a graphite block and measured the wavelength of the x-rays before and after they were scattered as a function of the scattering angle.
Compton was able to account for and derive the correct expression for the shift in wavelength.
Compton argued that the shift in wavelength is a result of a single photon imparting momentum to a single electron; thus the theory is derived from the laws of conservation of energy and momentum.
venables.asu.edu /quant/proj/compton.html   (779 words)

  
 SPEED OF LIGHT
Compton scattering is the scattering of photons of electromagnetic radiation from (quasi-) free electrons in matter.
The energy of the scattered photon is lower than that of the incident photon because the electron (originally at rest) exits with some of the energy.
The energy E’ of the scattered photon is related to the energy E of the incident photon by
www.phys.ksu.edu /personal/cocke/classes/phys506/COMPTON.htm   (768 words)

  
 Compton Scatter Polarimetry   (Site not responding. Last check: 2007-09-11)
is the frequency of the scattered photon, q is the scattering angle of the scattered photon measured from the direction of the incident photon, and h is the azimuthal angle of the scattered photon measured from the plane containing the electric vector of the incident photon.
In general, a Compton scatter polarimeter consists of two detectors to determine the energies of both the scattered photon and the scattered electron.
The area of the scattering detector which is exposed to the photon beam is also an important factor in determining the effective area of the polarimeter.
astrophysics.sr.unh.edu /GRAPE_Polarimetry.html   (822 words)

  
 X-Ray Crystallography Notes   (Site not responding. Last check: 2007-09-11)
Because the scattered intensity is inversely proportional to the square of the mass of the particle emitting the X-ray photon, scattering of X rays from the nucleus is considered negligible compared to the scattering from the electrons of an atoms.
Scattering factors are calculated assuming that the frequency of the incident radiation is different from any natural absorption frequency of the atoms.
This type of scattering is primarily a function of the atom type and the type of radiation, and is generally independent of the scattering angle.
xrayweb.msg.ku.edu /notes/crystallography.html   (5053 words)

  
 Compton Scattering
It is found that the scattered light has a wavelength different than that of the incident light, an effect that again cannot be explained using a wave picture of light, where the wavelength does not change.
Compton analyzed this problem by considering light as a photon with energy given by Planck's hypothesis, Eq.(27.5), as well as a momentum given by
Such a small difference in wavelengths between the incident and scattered light is very hard to detect using visible light, with wavelengths of the order of 500 nm.
theory.uwinnipeg.ca /physics/quant/node4.html   (189 words)

  
 COMPTON SCATTERING   (Site not responding. Last check: 2007-09-11)
Compton scattering of gamma rays is discussed in the companion notes, "Compton Scattering".
The object of this experiment is to measure the energy and relative scatter interaction rate as a function of scatter angle for a beam of monoenergetic gamma rays impinging upon a target of known material.
Move the detector to a small scatter angle, so that the area projected by target to the beam is maximized.
www.me.wpi.edu /Nuclear/Reactor/Labs/L-cs.html   (605 words)

  
 The Sunyaev-Zeldovich Effect   (Site not responding. Last check: 2007-09-11)
In this case, the easiest way to understand Compton scattering is to visualize a photon as a particle of light.
When such a photon passes through a cluster atmosphere, its typical energy gain due to Compton scattering is a miniscule 0.05%.
The "missing" photons were shifted, on average, to higher energy by Compton scattering.
science.nasa.gov /newhome/headlines/compton.htm   (327 words)

  
 Lecture 7 : Compton Scattering
, the scattering is modified by the appearence of quantum effects, through a change in the kinematics of the collision, and an alteration of the cross-section.
In this case the scattering cross-section is independent of the photon energy and is approximately equal to the Thomson cross-section.
In strong Comptonisation, the photon energy is increased until the electron and photon energy distributions approach equilibrium, i.e.
www.astro.utu.fi /~cflynn/astroII/l7.html   (1386 words)

  
 Landmarks: Photons are Real
Compton reasoned that in a direct test, when a light quantum collides with a free electron, the two should scatter from the collision like billiard balls across a pool table.
Using the conservation laws, Compton predicted the wavelengths of photons and speeds of electrons emerging at different angles from the collision.
and gamma rays, Compton found what he called "remarkable agreement between experiment and theory." The data were inconsistent with the wave theory, which predicted that the scattered light would spread in all directions, like water waves radiating from a stone dropped in a pond.
focus.aps.org /story/v13/st8   (533 words)

  
 Inverse Compton scattering
Lower energy scattered photons are generated farther from the pulsar, and so tend to be suppressed by the termination of the wind.
the TS is very close to the pulsar where inverse Compton scattering is still very efficient because the target photon density is large and the scatterings are close to head on.
The termination of the wind therefore has little effect in reducing the inverse Compton emission in this period, and the light curve from the terminated wind is indistinguishable from that of an unconfined wind.
www.atnf.csiro.au /pasa/18_1/ball/paper/node3.html   (1630 words)

  
 Compton scattering
Compton scattering is the scattering of a photon, such as an x-ray or gamma ray, by a massive particle such as an electron, usually taken to be at rest.
We denote the energy of the incident photon by Q and that of the scattered photon by Q'.
Since the right hand side of this equation is always positive, the scattered photon has a lower energy than the incident photon.
www.public.iastate.edu /~edsall/physics/hep/relativity/Notes/book/node169.html   (161 words)

  
 Compton Scattering
The scattering of photons from charged particles is called Compton scattering after Arthur Compton who was the first to measure photon-electron scattering in 1922.
When the incoming photon gives part of its energy to the electron, then the scattered photon has lower energy and according to the Planck relationship has lower frequency and longer wavelength.
The formula presumes that the scattering occurs in the rest frame of the electron.
hyperphysics.phy-astr.gsu.edu /hbase/quantum/compton.html   (173 words)

  
 On the relevance of Compton scattering for the interpretation of spectra of the LETGS DA white dwarf standard candles ...   (Site not responding. Last check: 2007-09-11)
The scattering of radiation by free electrons is one of the dominant sources of continuous opacity in the atmospheres of hot white dwarfs.
Å, and Compton scattering effects are expected to be smaller in Sirius B than in HZ43, the Madej (1998) calculations suggested that Compton scattering is not relevant to the use of DA white dwarfs as LETGS standard candles.
The solid line is the Comptonized spectrum of a pure H model, whereas the dashed line is the Thomson scattering spectrum.
hea-www.harvard.edu /~jdrake/memo/compton_scattering   (1354 words)

  
 Electron
Compton scattering is related by crossing symmetry to pair annihilation:
It can be seen that the electron on the left side of the Compton process can be replaced by its antiparticle, the positron, on the other side of the interaction resulting pair annihilation.
The Compton effect, discovered by Compton in 1923, provided the final confirmation of the validity of Planck’s quantum hypothesis that electromagnetic radiation came in discrete mass less packets (photons) with energy proportional to frequency.
teachers.web.cern.ch /teachers/archiv/HST2002/Bubblech/mbitu/electron-positron.htm   (473 words)

  
 Experiment 6. COMPTON SCATTERING OF GAMMA RAYS
In the elastic scattering of a photon through angle a by a free electron initially at rest, the energy E' of the scattered photon is given in terms of the energy E of the incident photon and rest energy of the electron, mc
The scattered flux is proportional to the total number of scattering centers (free electrons) in the beam.
Analysis of scattering angles is simplified by using the average scattering angle.
www.wsu.edu /~collins/Phys415/writeups/Compton.htm   (824 words)

  
 Graduate Physics Laboratory Handbook: Compton Effect
A simple experiment consisting of a verification of the energy formula for the Compton effect (and thereby the quantum nature of electromagnetic radiation) can be done using coincidence of the pulses from movable NaI(Tl) scintillator and a fixed plastic scintillator.
Alternate possibilities are to verify the Klein-Nishina formula for the intensity of scattered Compton radiation, in which case the efficiency of the NaI crystals enters, or to check the simultaneity of the two emitted photons, in which case a time-to-amplitude converter may be used on the scintillator outputs.
This is an article on the history of Compton scattering.
www.physics.umd.edu /studinfo/courses/gradlab/glhb/compton.html   (459 words)

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