x rays

[RichIsnang]

I heard that X-Rays cannot be reflected, is this true?

and if so why?

[mississippichem]

No,

 

IIRC x-ray reflection can be used to characterize the surface morphology features of certain materials. Not something I know much about but I know the technique exists.

[Klaynos]

No,

 

IIRC x-ray reflection can be used to characterize the surface morphology features of certain materials. Not something I know much about but I know the technique exists.

 

I think you're talking about Bragg diffraction. It does require reflection of x-rays.

 

 

http://en.wikipedia.org/wiki/Bragg's_law

[swansont]

There are grazing-incidence mirrors for x-rays

 

http://en.wikipedia.org/wiki/X-ray_optics

[RichIsnang]

I learnt about the grazing mirrors and was told (by an undeniable source, I might add) that x rays can't be reflected directly by 180 degrees in the way that visible light can. Is there no truth in this? If not then Why do they use grazing mirrors?

Edited June 11, 2012 by RichIsnang

[Enthalpy]

Suggestion: as X-rays have a significant momentum, they lose energy to the expelled electron if reflected back, and as this energy loss differs randomly at each electron due to random impact parameter, individual interactions don't sum up coherently so they can't make an efficient reflection. As opposed, grazing reflection loses little momentum and energy so the contributions of all electrons can sum up coherently. Even better if the angle is such that electrons aren't expelled nor excited, in which case the photon loses no energy, and phase is coherent over all events.

 

Hey, this would even sound credible!

 

One more effect is that, as reflection is done over several atomic layers which make several wavelengths at X-rays, light reflected from these layers doesn't add coherently in the 180° direction. It does add up at longer wavelengths or at grazing reflection.

 

Maybe a "crystal" of protons or alphas or stripped ions in an ion trap, preferably neutralized by baryonic antimatter, would make a better X-ray reflector than electrons do. Still far-fetched technology in 2012.