What is Compton scattering: Definition and 166 Discussions

Compton scattering, discovered by Arthur Holly Compton, is the scattering of a photon after an interaction with a charged particle, usually an electron. If it results in a decrease in energy (increase in wavelength) of the photon (which may be an X-ray or gamma ray photon), it is called the Compton effect. Part of the energy of the photon is transferred to the recoiling electron. Inverse Compton scattering occurs when a charged particle transfers part of its energy to a photon.

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  1. S

    Simple calculation of Compton scattering in string theory

    Hallo. So the other day I reviewed a bit of quantum field theory and went through the Compton scattering calculation. To no ones surprise it was fairly simpel if you have a nice list of identities for rewriting the base results from the Feynman diagrams. See for exaxmple section 5.3 in...
  2. Avatrin

    Conservation of momentum in compton scattering

    Hi I recently got some weird feedback on homework. It said that "..momentum is only conserved componentwise..". The problem involved Compton scattering, and I had used p_{\lambda,1} = p_{e,2} + p_{\lambda,2} to find p_{e,2} for collision between an electon and a photon. I had used the...
  3. Harry Atkinson

    Compton Scattering: Find scatter angle of electron & Vf

    Homework Statement http://oi58.tinypic.com/2zitybl.jpg Homework Equations As above The Attempt at a Solution [/B] Rearranging the above equations to remove unknowns, finally substituting new equations into the compton effect equation. Will post up next page as I fill it, - is it acceptable...
  4. U

    Cobalt decays to Nickel - Why is this suppressed?

    Homework Statement (a) Show maximum energy transferred in compton scattering is as such. (b) Identify what the peaks are and why some decays are suppressed. (c) How do you distinguish between these 2 decays[/B] Homework EquationsThe Attempt at a Solution Part(a) Bookwork. For completeness...
  5. A

    Photoelectric effect and Compton scattering

    Homework Statement A photon with of 13600eV energy interacts with a hydrogen atom at rest and ejects the electron (photoelectrically) in the direction in which the photon was travelling. If 13.6 eV is required to eject the electron, find the speed of the photoelectron and the momentum and...
  6. U

    'Special' fourth order Feynman diagram Compton Scattering - Why is it allowed?

    I thought the fundamental electromagnetic vertex is Why is the following diagram below allowed? The 'special' feynman diagram for compton scattering ##e^- + \gamma \rightarrow e^- + \gamma## is
  7. A

    Derivation of Ee in Inverse Compton Scattering

    Homework Statement In the inverse compton scattering, find the formula of the recoiled electron as a function of the incoming electron Homework Equations The energy of the incoming photon and electron are known. The Attempt at a Solution Starting from this...
  8. J

    Compton scattering differential cross section

    1. The problem statement, all variables and given/known I have to prove an equation for the differential cross section of compton scattering of an electron and a photon (electron (P) + photon(K) ⇒ electron(P') + photon (K') ) where P and so on are the inital and final four momenta. Given is...
  9. Fosheimdet

    Compton scattering; conservation of momentum violated?

    While reading the derivation of the formula \lambda' - \lambda = \frac{h}{ m_ec}(1-cos(\theta)) on Wikipedia, they point out that the momentum gained by the electron is larger than the momentum lost by the photon: $$ p_e=\frac{\sqrt{h^2(\nu-\nu')^2 +2h(\nu-\nu')m_ec^2}}{c} >...
  10. U

    Compton Scattering Angle - CM FRAME

    Homework Statement Given incoming photon has energy 10Mev and scatters at angle 25 degrees, find the scattering angle in CM frame. Homework EquationsThe Attempt at a Solution [/B] In lab frame, let the energy of incoming photon be ##E##. Total 4-vector would be ##P + Q =...
  11. O

    How Does Compton Scattering Affect Photon Wavelength in the Sun?

    Homework Statement Nuclear fusion reactions at the center of the sun produce gamma - ray photons with energies of about 1 MeV (10^6 eV). By contrast, what we see emanating from the sun's surface are visible light photons with wavelengths of about 500nm. A simple model that explains this...
  12. O

    Compton Scattering of a photon

    A photon with wavelength lambda = 0.1050 nm is incident on an electron that is initially at rest. If the photon scatters at an angle of 60.0 degrees from its original direction, what are the magnitude and direction of the linear momentum of the electron just after the collision with the photon...
  13. kini.Amith

    How does Compton scattering suggest photons?

    I have seen many 'photoelectric effect vs compton effect' Questions in this and other forums, but i am still not convinced. I can see how photoelectric effect points to the particle nature of light. But i don't see how compton effect as a separate experiment is needed to confirm this. The only...
  14. S

    Compton scattering theory question

    The question is this: When a photon bounces off an electron, it gives some of its energy to the electron. The photon has no mass, however, and it must continue to travel at speed c. How is its reduced energy manifested? Now, I do somewhat understand what the Compton effect is and I read in my...
  15. C

    Can someone explain Compton scattering?

    Hi, My textbook describes Compton scattering the following way: "...an x-ray photon...has a collision with a slow moving electron...the photon transfers energy and momentum to the electron [and recoils]..." Is it not true that by definition when a photon collides with a particle it...
  16. johann1301

    Compton scattering and momentum

    If a photon collides with an electron not moving, and you know the momentum of the photon before and after, and the electrons momentum, is it possible to know the direction of the electron and the photon after the collision?
  17. M

    Compton scattering - energy of the scattered photon

    [Mentor's note: This thread does not use the template because it started in one of the non-homework forums. I moved it here instead of deleting it and asking the poster to repost here, because it had accumulated several useful replies.] Hi. I have the exact same problem that ZachWeiner had in...
  18. B

    Compton scattering is inelastic?

    I have a couple of simple questions: - wiki says (http://en.wikipedia.org/wiki/Compton_scattering) that it " is an example of inelastic scattering". Is that true?, isn't all energy lost by the photon absorbed by the electron? - is the electron really at rest? doesn't his energy/momentum...
  19. C

    Compton scattering, formulae question

    Homework Statement An X-ray source of wavelength gamma is directed at a sample; determine the maximum speed of scattered electrons.Homework Equations KE=(\gamma-1)mc2=hc/\lambda - hc/\lambda' The Attempt at a Solution I've been provided with the solution using the formula above, however it...
  20. S

    Relative angle after Compton scattering?

    Homework Statement Photon with ##\lambda =10^{-12} m## hits an electron (Compton scattering). After the interaction the photon and electron move under relative angle of 90°. Calculate the kinetic energy of electron. Hint: First find the relation between ##\theta ## and ##\varphi##. (##\theta...
  21. B

    Quantum Mechanics Help. Compton Scattering Use.

    Homework Statement In a Compton scattering experiment, a photon is scattered through an angle of 90.0deg, and the electron is scattered through an angle of 21.4deg. Determine the wavelength of the scattered photon Homework Equations Conservation of momentum and energy. p = h/lambda, E =...
  22. 7

    Compton scattering - no solution from quadratic eq? What to do?

    Homework Statement Incomming photon gives half of its energy to an electron during scatering. After scattering, photon is headed ##\phi=120^\circ## according to the original direction. What is the ##\lambda## of the incomming photon? Homework Equations \begin{align} \Delta \lambda &=...
  23. Q

    How Does Compton Scattering Affect Photon Wavelength at 90 Degrees?

    Homework Statement The length of the photon waves which are under Compton scattering ( compton scattering is applied on them) is measured in the angle =90 degree.If ΔΛ/Λ is 1.5 %,what is the length of the waves of the falling photons? Homework Equations The Attempt at a Solution...
  24. M

    What happens after Compton scattering event?

    Hi All, So the photoelectric effect is the phenomenon where an orbital electron fully absorbs an incoming photon (assuming the energy of the photon is greater than the binding energy of the electron) and is ejected from its shell. The electron can then undergo its own interactions in the...
  25. D

    Photoelectric effect and Compton Scattering statements.

    Provide one of the following answers: PE,CS, BOTH, OR NEITHER. PE if the statement applies only to Photoelectric Effect. CS if the statement applies only to Compton Scattering BOTH if the statement applies only to both the Photoelectric Effect and Compton Scattering. NEITHER if the...
  26. C

    Different approximations of Compton scattering equation

    Homework Statement Show that, for low energy photons scattered by ultrarelativistic electrons, the cange in frequency of the photon is given by (v'-v) / v = [(Ω'-Ω).β] / [1-Ω'.β] Homework Equations The full/general form of Compton scattering is given by v'/v = (1-Ω.β) /...
  27. C

    Non-relativistic limit of Compton scattering -Taylor expansion?

    Homework Statement In the non-relativistic limit, the equation for Compton scattering is v' / v = 1 / (1+x) where x = (hv/mc2)(1-Ω.Ω') Show that the change in frequency Δv = v' - v is given by Δv / v = -x Homework Equations The Attempt at a Solution I rearranged the...
  28. D

    Does Multiple Compton Scattering Occur in Laser-Electron Interactions?

    I'm testing my faith in the photon. I understand that energy levels are quantized, and I understand that the EM field carries momentum. I want to make sure the idea of a photon is necessary to intuitively understand the observations. I am focused on compton scattering of a photon and an...
  29. Z

    Photon with negative energy, Compton Scattering

    Hello PF people, Homework Statement In a Compton scattering event, after the collision, the Photon has an energy of 0.12 MeV and the Electron has an energy of 0.04 MeV. Find the following: i) The Wavelength of the photon before the collision. ii) The scattering angle for the photon...
  30. B

    What is the maximum energy an electron can have after scattering a 40keV photon?

    Homework Statement A photon carrying energy of 40keV scatters from an electron initially at rest. what is the maximum energy the electron can have? Homework Equations The Attempt at a Solution I tried using conservation of energy Initial: 40keV (energy of photon) + mc^2...
  31. Bailey

    Compton scattering and collision within blackbody

    Homework Statement Consider a blackbody contain atoms that typically produce photons with energy of about 7eV. Estimate the number of photon-electron collision each photon undergoes before it escape the object. Assume the blackbody has a temperature of 1000K. Homework Equations λ2 - λ1...
  32. M

    Find the Wavelengths of Compton Scattered Photon and Original Photon

    Homework Statement Okay, so here's the problem: In a Compton scattering experiment, a photon is scattered through an angle of 90.0 and the electron is set into motion in a direction at an angle of 20.0 to the original direction of the photon. (a) Explain how this information is...
  33. I

    Time-scale of Compton scattering

    Hey all, Anyone know if there is a δt to Compton scattering or is it an instantaneous event, entertaining classical physics...billiard balls colliding in an elastic collision. Cheers
  34. H

    Photoelectric effect and Compton scattering difference

    What is the difference between the two ? Maybe that in the photoelectric effect all of the energy of a photon is absorbed by the electrons ? Is that it ? In Compton scattering, only part of the energy is absorbed hence there is a photon of lower frequency emitted ! OR Maybe in the...
  35. E

    Wavelength of scattered photon and angle of scattering in the Compton scattering

    Homework Statement In the Compton scattering, a photon of wavelength λ collides with an electron at rest, and a new photon of wavelength λ' emerges at an angle θ. Find λ' y θ. Energy of incident photon Ei = 1 MeV Energy of scattered electron Ee = 0.32 MeV Homework Equations E =...
  36. I

    Electron velocity after Compton Scattering

    Homework Statement In Compton scattering,how much energy must the photon have in order for the scattered electron to achieve relativistic velocity? Homework Equations Compton scattering formula: $$λ'-λ=\frac{h}{mc}(1-cosθ)$$ ##E=\frac{h}{λ}##,conservation of mass and momentum,possibly...
  37. D

    Finding the Kinetic Energy of Compton Scattering

    Homework Statement X-ray photons of wavelength 0.02480 nm are incident on a target and the compton-scattered photons are observed at 90 degrees.(a) What is the wavelength of the scattered photons?(b) What is the momentum of the incident photon and scattered photon? (c) What is the kinetic...
  38. U

    Compton scattering when E mc^2

    Homework Statement Consider Compton scattering of a photon by a moving electron. Before the collision the photon has a wavelength λ and is moving in the positive x direction. The electron is moving in the negative x direction with a total energy E ( including rest energy mc^2). The photon and...
  39. M

    Photoelectric effect vs Compton scattering

    I understand that in photoelectric effect, the energy of the whole photon is absorbed, freeing an electron. I don't understand why in the case of Compton scattering, the higher energy photon lost part of its energy instead of transferring the whole of its energy to the electron as in...
  40. D

    Compton scattering problem - how much did wavelength change by?

    Homework Statement How much will the wavelength of the incident X-ray photon change by if it is scattered by 30 degrees when it interacts with an electron? Homework Equations This is Compton scattering. This is the equation I used: lambda ' - lambda (0) = (h)/(m(e)c) (1-cos...
  41. D

    Compton Scattering: Largest Shift & Min Energy Transfer

    assume that a photon scattered by an electron initially at rest. which photon scattering angle corresponding to the largest compton shift and why? At what minimum photon energy can half of the photon energy be transferred onto the electron ??
  42. M

    Photo-electric effect, Compton Scattering

    Homework Statement What is the maximum kinetic energy of electrons knocked out of a thin copper foil by Compston scattering of an incident beam of 17.5 KeV rays? Assume the work function is negligible. Homework Equations Δλ = h/mc (1-cosθ) The Attempt at a Solution I reasoned...
  43. N

    Why do photons/electrons scatter at angles in compton scattering?

    This is something that I always just took for granted, but I have no idea how a photon scatters off of an electron at an angle other than 0 or 180 degrees. I haven't seen this mentioned in a modern physics or nuclear engineering textbook either, so I assuming its a pretty complicated reason?
  44. D

    Undefined angles for Compton scattering

    Homework Statement Hello, I need to find which values for θ and ψ are not defined for the Compton scattering. Where θ is the angle of the electron and ψ is the angle for the photon.Homework Equations I have attached the formulas I´m using. http://tinypic.com/view.php?pic=v4z2qf&s=5The Attempt...
  45. A

    Compton Scattering of a photon by a moving electron

    Homework Statement If the total energy of the electron E>>mc^{2} Prove that the formula of wavelength would be \lambda '=\frac{hc}{E}(1+\frac{m^{2}c^{4}\lambda}{4hcE}) where \lambda ' is the wavelenght after scattering m is the mass of electron Homework Equations The Attempt at a...
  46. L

    Why does CT utilise compton scattering?

    why does conventional xray imaging utilise photoelectric effect but ct utilise compton scattering? i know that at different energies, different mechanisms (eg compton scattering, photoeletric effect, pair production) dominate but do they not chose the energy beam to correspond the process that...
  47. 1

    Compton Scattering: Finding Angle from only Initial Energy

    Homework Statement Gamma rays of energy 1.02 MeV are scattered from electrons that are initially at rest. If the scattering is symmetric, that is, if θ = ϕ in Fig. 1, find i. the scattering angle θ ii. the energy of the scattered photons. Homework Equations λ' - λ = (h/mc)[1 - cos(θ)] The...
  48. S

    Compton Scattering: Calculating Fractional Wavelength Shift

    Some one please tell me how to calculate fractional shift of scattered wavelength of photon in terms of campton wavelength
  49. A

    Compton Scattering given Energy of Scattered Gamma.

    Homework Statement Gamma rays of energy 1.02MeV are scattered from electrons which are initially at rest. Find the angle for symmetric scattering at this energy. What is the energy of the scattered photon from this case? Homework Equations \Delta \lambda = 0.0243A (1 - cos \theta )...
  50. G01

    QFT- Compton Scattering Crossection

    Homework Statement I'm working through the derivation of the Compton scattering crossection and I'm getting stuck partway through. More details below: Homework Equations The Attempt at a Solution So, I'm following along with Zee section II.8. We have two diagrams that contribute to order...
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