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

    B Electron's movement after getting hit by a photon that bounces at 90 degrees

    I just started studying Quantum physics and i'm learning about Comptonspreading and I have this question in my book that I don't completely understand So if an electron is standing still, then it gets hit by a photon moving in a straight line into the electron. The photon then bounces off the...
  2. J

    Electron in a light microscope

    Hello everyone, I solved the problem above in the following way: 1. ##E_{Ph} = 124##keV 2. ##E_e = E_{Ph} - E_{Ph'}## ##E_{Ph}## is the energy of the incoming photon, ##E_{Ph'}## is the energy of the photon, after the scattering with the electron (I am using the formulas assuming there is...
  3. Marioweee

    Compton scattering with off-shell photon

    How is it treated or what Feymann's rule applies to a virtual photon in an external leg? I would like to calculate the modulus of squared amplitude for the process e-γ*→e-γ where the * indicates that the photon is virtual. I've never dealt with virtual particles on a external leg and would...
  4. C

    I Annoying detail in derivation of Compton scattering

    In Compton's 1923 paper on X-rays scattering from light elements, he presents the following diagram: Here, ## h\nu_0/c ## is the momentum of the incident photon, ## h\nu_\theta/c ## is that of the scattered photon and ## mv/(1-\beta^2)^{1/2} ## is that of the recoiled electron. He uses this to...
  5. Viona

    I Compton scattering experiment

    I was reading about Compton scattering. I have a question I did not find an answer for it in the book (Concepts of Modern Physics-Sixth Edition-Arthur Beiser) or in the internet search. My question is: Is the incident X-ray beam, with the original wavelength, detected at different scattering...
  6. D

    B Compton Scattering and Inverse Compton Scattering

    Hi, Is there a more general equation than the Compton equation that allows one to determine whether an electron will Compton scatter or inverse Compton scatter? If so, where can I find it (or what is it?) Thanks.
  7. neilparker62

    I Online Experiment: Compton Scattering

    I recently thought it might be interesting to see if there were any online simulations or videos of Compton Scattering experiments. The search result yielded following: Given the standard equation: $$1-\cos\theta_d=\frac{E_0 \Delta E}{E_1 E_2} ,$$ we should get a straight line with gradient...
  8. A

    B Using Compton Scattering to Determine Interaction Depth in Materials

    If I have a material with some thickness , say 0.5 meters and I have an incoming gamma photon that undergoes Compton scattering. The gamma ray loses some energy and is shifted in angle with respect to it's original trajectory and leaves the material. The electron gaining KE in the interaction is...
  9. neilparker62

    I Nature of Collision in Compton Scattering

    I am just wondering how best to visualise a Compton scattering event. Since a photon has no mass, we can't exactly presume it's the same as two masses colliding even if at relativistic speeds. Does the photon encounter some kind of force field as it approaches the stationary electron ? If so...
  10. J

    Compton Scattering - Find x component of electron momentum

    So I can find the initial momentum using p=h/wave = 4.98 x 10-23. Now my problem is that I don't know the final momentum of the photon nor electron, I just know the photon is scattered at an angle of 34 degrees. I know how to solve this problem if I was given the final wavelength of the light...
  11. J

    Compton Scattering - determine momentum

    So the initial wavelength gives the total momentum, p=h/11.2p. Which is 59.161y. Then I tried to substract the momentum from the scattered light to get the momentum of the electron. 59.161y-h/13.6p, which ends up being 0.4872 as the final answer, but the answer is supposed to be 0.77?
  12. B

    Compton Scattering: K, Wavelength Calculation

    K= 1/2 (9.11*10^-31)(8.2*^6)^2 (wl)' = hc/k = 6.5 nm (wl)' - (wl) = 6.36 nm cos(theta) = 1- (((6.36nm)(9.11*10^-31)(3*10^8))/(6.63*10^-34)) = -2620.7 theta = error
  13. B

    Relationship between spectral distribution and Compton scattering

    First of all, this is question from the modern physics module in 1st year physics program. The problem is I have no prior knowledge about spectroscopy or Lorentzian profile. However, the Compton scattering topic was already introduced. The Compton scattering formula can be changed into the...
  14. JD_PM

    Showing Feynman-amplitudes' gauge invariance (for Compton Scattering)

    Show that the Feynman amplitude for Compton scattering ##\mathcal{M} = \mathcal{M}_a + \mathcal{M}_b## is gauge invariant while the individual contributions ##\mathcal{M}_a## and ##\mathcal{M}_b## are not, by considering the gauge transformations $$\varepsilon^{\mu} (\vec k_i) \rightarrow...
  15. F

    Exploring Compton Scattering and Backscatter Scanners

    I'm researching a bit on Compton Scattering, especially in relation to, backscattering scanner, like one would see in an airport. I think I understood that the angle of deflection is in relationship to the loss of energy of the photon, where λf - λi = h/mc(1-cosθ). So if you know the...
  16. C

    Compton Scattering: Determining the Energy of a Scattered Gamma Ray

    I'm unsure of how to proceed here. Would I use the equation E(gamma prime)= E(gamma)/(1+(E(gamma)/(mc^2)(1-cos(theta))) ? Also, do I keep the .662 Mev as is or do I convert to joules?
  17. JD_PM

    I How does the experimentalist deal with Compton Scattering?

    I've been studying Compton Scattering (Mandl & Shaw, https://ia800108.us.archive.org/32/items/FranzMandlGrahamShawQuantumFieldTheoryWiley2010/Franz%20Mandl%2C%20Graham%20Shaw-Quantum%20Field%20Theory-Wiley%20%282010%29.pdf) and the derivation of the following formulas: 1) Differential cross...
  18. JD_PM

    I How Do You Calculate Traces in Compton Scattering Feynman Amplitudes?

    Given the Feynman amplitude (Compton Scattering by electrons) ##\mathscr{M}=\mathscr{M}_a+\mathscr{M}_b##, where $$\mathscr{M}_a = -i e^2 \frac{\bar u' \not{\!\epsilon'} (\not{\!p}+\not{\!k}+m) \not{\!\epsilon} u}{2(pk)}, \ \ \ \ \mathscr{M}_b = i e^2 \frac{\bar u' \not{\!\epsilon}...
  19. JD_PM

    I Understanding the (polarized) cross section for Compton Scattering by electrons

    I have specific questions, but let's first give context. Initially we have an electron with momentum ##p=(E, \vec p)## and spin state ##u_r (\vec p)## and a photon with momentum ##k=(\omega, \vec k)## and polarization state ##\epsilon_s (\vec k)##. Finally we have ##p'=(E', \vec p')##, ##u_r'...
  20. neilparker62

    I Special Case of Compton Scattering

    Was just wondering if there's anything special about the physics of Compton scattering where the incident photon has the same energy (512 keV) as the electron at rest. Then: $$1−cosθ_d=\frac{E_0ΔE}{Ei Er}=\frac{E_0(E_0−Er)}{E_0E_r}=\frac{E_0}{E_r}−1=\frac{λ_r}{λ_0}−1 $$ $$⇒\frac{1}{E_r}\propto...
  21. jisbon

    Compton scattering event (Proof question)

    Hi all, Currently given a problem to prove that the scattered photon is fixed at a constant value with only the condition that both angles from the photon and electron sum up to 90 degrees after the collision. I can't seem to prove it and listed my steps below, was wondering if anyone can...
  22. jim421616

    I Can Compton scattering increase the energy of photons?

    I've read (in Hagai Netzer's book The Physics and Evolution of Active Galactic Nuclei) that "Comptonization in the [black hole's accretion] disk atmosphere can increase the energy of some photons..." I thought Compton scattering could only decrease a photon's energy. What am I missing?
  23. f77hacker

    A Rayleigh length to electron bunch emittance

    Hello, Context is Inverse Compton Scattering with an pulsed electron beam interacting with a pulsed laser. A laser has a Raleigh length of Z_r = w_o^2 * pi / lambda w_o is the the radius of the spot size, lambda is the laser frequency. I want to match this spot size to a pulsed electron bunch...
  24. W

    A Questions from Peskin & Schroeder 5.5 about Compton Scattering

    Hi! Just a couple questions on the Compton scattering calculation in P&S. I feel like I'm missing something very simple here but can't quite figure out what it is. On page 166, the amplitude to be evaluated is $$ i\mathcal M = -ie^2 \epsilon_\mu(k)\epsilon^*_\nu(k^\prime) u_R^\dagger(p^\prime)...
  25. Rafiki

    [Compton scattering] Solving for wavelength

    Homework Statement Question: Determine the energy of the incident photon when the recoiled electrons energy is measured to 3 MeV. The angle between the incident photon and the scattered photon is 60°. Given and knowns: θ=60° (Angle between incident photon ##\gamma## and scattered photon...
  26. nomadreid

    I Compton scattering in a Feynman diagram

    Attempting to understand the following: Compton scattering can happen either (a) an electron could absorb a photon and later emit a photon, or (b) an electron could emit a photon and later absorb a photon. OK, the maths works out, but I am trying to get intuition on track. These two are...
  27. P

    Compton Scattering- finding photon wavelength

    Homework Statement An electron moving to the left at 0.8c collides with an incoming photon moving to the right. After the collision, the electron is moving to the right at 0.6c and an outgoing photon moves to the left. What was the wavelength of the incoming photon? Homework Equations p=γmv...
  28. D

    Compton Scattering and Recoil Velocity

    Homework Statement A photon of wavelength ##\lambda_i = 200## pm hits an electron at rest, and is scattered exactly backwards. Find the approximate recoil velocity v of the electron using momentum conservation. Homework Equations Comptons Scattering: $$\lambda_f = \lambda_i...
  29. S

    I Massless Electron Compton Scattering: Energy of Outgoing Photon

    Hello! I found this problem where we are asked what happens to the energy of the outgoing photon in a Compton interaction, if the mass of the electron goes to zero and what is the physical intuition of it. So the formula is this: $$\lambda - \lambda_0 = \frac{h}{m_0 c}(1-cos \theta)$$ So when...
  30. K

    I Compton Scattering w/Moving Electron: Turner's Eq 5.29

    I beg your pardon for not writing out the math explicitly in the following. I started to do so, and realized that it would take me hours to debug my attemps at Latex! And I hope that the my explanation is clear enough that it's not needed. I've been working through R.E. Turner's "Relativity...
  31. A

    Special relativity - inverse Compton scattering

    Homework Statement In the inverse Compton scattering there is a particle, with energy ##E## in the laboratory frame and mass at rest ##m##, which collide head on with a photon with energy ##E_\gamma##. Finding the maximum energy the photon can have after being scattered. The Attempt at a...
  32. R

    Compton Scattering Homework: Wavelength & Angle Calculation

    Homework Statement In a Compton scattering experiment, an x-ray photon scatters through an angle of 17.40 from a free electron that is initially at rest. The electron recoils with a speed of 2180 km/s. Calculate (a) the wavelength of the incident photon and (b) the angle through which the...
  33. Pushoam

    Compton Scattering: Solving for E with $\phi = 1/4\pi$

    Homework Statement Homework EquationsThe Attempt at a Solution ## \lambda' = 2 \lambda ## ## \lambda' - \lambda = \lambda = \frac { h} { mc} \cos{ \phi } ## Here, ## \phi = \frac { pi} 4 ## is the angle between photon's original line of motion and its line of motion after...
  34. A

    I Is the Compton scattering angle related to the incident energy?

    The Compton equation determines the shift of the wave-length of the scattered photon as a function of the ##cos\theta## of the scattered photon. It does not depend on the energy of the incident photon. With some manipulation using the equations of conservation of the momentum and energy, one...
  35. Pouyan

    Calculating the Wavelength of Monochromatic Radiation in Compton Scattering

    Homework Statement Compton scattering can be used both to measure the direction and energy of photons in nuclear physics experiments. For a particular preparation a spectrum of Compton scattered electrons was measured which clearly corresponded to a generally monochromatic gamma radiation. The...
  36. Daniel Petka

    B Is Inverse Compton Scattering Related to the Doppler Effect?

    Isn't Inverse Compton scattering just the Doppler's effect? A fast moving electron gets slowed down by a photon. This photon then becomes blue shifted, becoming a gamma ray. Kinda makes sense.
  37. Albi Mema

    Consider Compton scattering of a photon by a moving electron

    Homework Statement Consider Compton scattering of a photon by a moving electron. Before the collision the photon has wavelength λ and is moving in the +x-direction, and the electron is moving in the −x-direction with total energy E (including its rest energy mc2). The photon and the electron...
  38. H

    Compton Scattering Angle Calculation

    Homework Statement A photon with wavelength 0.1385 nm scatters from an electron that is initially at rest. What must be the angle between the direction of propagation of the incident and scattered photons if the speed of the electron immediately after the collision is 9.30×106 m/s? Homework...
  39. cdot1989

    I Photoelectric absorption versus Compton scattering

    During the photoelectric process, photons are absorbed and electrons are ejected. In Compton scattering, photons are scattered rather than absorbed. My textbook (Quantum Physics of Atoms,Molecules,Solids,Nuclei, and Particles) explains that absorption occurs in the photoelectric process because...
  40. C

    I One loop corrections to Compton scattering

    At next to leading order, a photon may couple to gluon via means of a quark loop insertion. Consider the process $$ \gamma(k_1) + g(p_1) \rightarrow \gamma(k_2) + g(p_2)$$ Apparantly there are eight diagrams at one loop contributing to this process and two are zero on grounds of colour...
  41. Magnetic Boy

    Fraction of lost energy in compton scattering

    Homework Statement After undergoing through 90° compton scattering, the fraction of energy lost by photon is a) 10% b) 20% c) 50% d) zero e) none of these Homework Equations ∆λ= h/moc (1-cosΦ) The Attempt at a Solution What i m doing is that, i get scattered photon energy and subtracting...
  42. Jim Lundquist

    A Lay Question Regarding Compton Scattering

    From what I understand, a photon of "sufficient" energy will interact with a free electron such that the recoil electron receives part of the energy of the photon, and the scattered photon has a Doppler shift (change in wavelength). If the scattered photon still has "sufficient" energy, Compton...
  43. Matt atkinson

    What is the maximum recoil energy of photons in Inverse Compton Scattering?

    Hello all, I'm just doing some practice for an upcoming exam and came upon this question in my notes: One experimental way to generate very high energy photons is to ”collide” a laser beam against an electron beam, the photons that recoil in the direction parallel to the electron beam will have...
  44. W

    Compton Scattering; Relation between scattering angles

    Homework Statement Show that the scatter angles of the photon (θ) and electron (Φ) in the Compton effect are related by the relation: ##cot (θ/2 )=(1+\frac{hf}{mοC^2}) tan(Φ) ## Where f is the frequency of incident photon 2. The attempt at a solution I wrote down the equations of conservation...
  45. C

    Few questions about photoelectricity

    First - Basic photoelectric effect demonstration setup: A charged battery with a gap in the metallic junction between the poles placed relatively close from each other, but not close enough for measurable current to occur spontaneously. Emit photons of sufficient energy towards the gap surfaces...
  46. carllacan

    What determines the Compton scattering angle?

    Hi. I've been reading about Compton scattering and I don't understand what determines the angle at which the electron and photon are scattered. Is it a quantum process, and therefore the value of the angle is "random"? If it is a quantum process, is there any theory that gives the probability...