Collisions of varying frequencys of Electromagnetic Radiation.

Click For Summary

Discussion Overview

The discussion centers on the interactions of photons of varying frequencies, particularly focusing on collisions involving gamma rays, X-rays, and visible light. Participants explore the potential outcomes of these collisions, including the formation of matter and the conditions necessary for such processes to occur.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants inquire whether photons of frequencies other than gamma rays, such as X-rays, can result in interactions beyond mere ricochet.
  • It is proposed that a gamma ray of sufficient energy can produce particle pairs when interacting with lower energy photons, provided both exceed 511 keV in a suitable frame of reference.
  • Questions are raised about the possibility of elastic scattering between two photons and how the cross-section for such scattering compares to that of pair production.
  • One participant suggests that if the energy in a collision exceeds 511 keV, it may be possible for multiple lower frequency photons to combine their energies to produce particles.
  • Another participant clarifies that the total collision energy must reach 1022 keV for particle production, noting that multiple photons can indeed contribute to this energy threshold.

Areas of Agreement / Disagreement

Participants express differing views on the conditions required for photon collisions to result in particle production, with some uncertainty regarding the specifics of photon interactions and the necessary energy thresholds.

Contextual Notes

There are limitations regarding the assumptions made about the frame of reference for photon interactions and the specific conditions under which particle production occurs. The discussion does not resolve these complexities.

Who May Find This Useful

This discussion may be of interest to those studying photon interactions, particle physics, or the theoretical aspects of electromagnetic radiation in various contexts.

Rorkster2
Messages
65
Reaction score
0
When Gamma Rays collide it is possible to form various units of matter (ie proton, electron, etc). Does anything happen when photons collide that are of other frequencies other then a ricochet? If X-Rays collide with other x-rays does anything happen? Also, if anything does happen, what would the result of something along the lines of a gamma ray collision with visible light?
 
Physics news on Phys.org
Rorkster2 said:
When Gamma Rays collide it is possible to form various units of matter (ie proton, electron, etc). Does anything happen when photons collide that are of other frequencies other then a ricochet? If X-Rays collide with other x-rays does anything happen? Also, if anything does happen, what would the result of something along the lines of a gamma ray collision with visible light?

DO they ricochet? And if yes, how often?

A gamma ray of sufficient energy can produce pairs with lower energy photons - as soon as a frame of reference exists where both are over 511 keV.

But can 2 photons undergo elastic scattering? And if yes, how does the cross-section for such scattering compare with the cross-section for pair production?
 
The cross-section for photon-photon interactions of all sorts is extremely small. There is always a frame of reference where both photons have the same energy and opposite momentum - you can consider all photon-photon interactions as "head on". If the energy is more than 2*511keV in this frame, it is possible to produce electron/positron pairs (and other particles, if the energy is high enough for them).
 
If energy in a collision is over 511kev, does that mean it would be possible for many lower frequency photons (i.e visible light or radio waves) to collide at a single point and have the combined energy over 511kev and result in particles?
 
Rorkster2 said:
If energy in a collision is over 511kev, does that mean it would be possible for many lower frequency photons (i.e visible light or radio waves) to collide at a single point and have the combined energy over 511kev and result in particles?

No, the collision energy must total 1022 keV. But yes, more than 2 is possible. After all, many electron-positron annihilations result not in 2 photons (with equal energies of 511 keV and opposite directions) but in 3 photons, of differing energies and directions totalling 1022 keV. It follows that it must also be possible for 3 photons to collide resulting in a pair, if the combined energy exceeds 1022 keV (in a suitable frame).
 
Thanks this has been helpful.
 

Similar threads

High School Can alpha radiation make other materials radioactive?
  • · Replies 8 ·
Replies
8
Views
4K
Graduate Why KE of Annihilation Electrons Differs?
  • · Replies 11 ·
Replies
11
Views
2K
Graduate Larger X-ray dose in traditional X-ray of head vs. Head CT?
  • · Replies 7 ·
Replies
7
Views
4K
High School What does QFT really predict about matter/anti-matter interactions?
  • · Replies 6 ·
Replies
6
Views
2K
High School Moving Center of Mass Collisions
  • · Replies 17 ·
Replies
17
Views
2K
Undergrad What would a hypothetical quark-quark collision yield?
  • · Replies 4 ·
Replies
4
Views
3K
Undergrad Gamma radiation, photon energies and wavelength question
  • · Replies 4 ·
Replies
4
Views
3K
High School Few questions about radioactivity/radiation
  • · Replies 10 ·
Replies
10
Views
3K
Undergrad Colorless Compounds and electromagnetic radiation
  • · Replies 19 ·
Replies
19
Views
4K
High School E- p+ collision product energies
  • · Replies 1 ·
Replies
1
Views
2K