Collisions of varying frequencys of Electromagnetic Radiation.

Main Question or Discussion Point

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?

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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?

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Mentor
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 enrgy over 511kev and result in particles?

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 enrgy 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.