Where could I look for down-to-earth X-ray facts?

  • #1
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Hello,

I'd like to know which book or papers I'd read to understand, possibly without too rigorous mathematics knowledge, how do photons like X-rays or gamma ones reflect off surfaces and attenuate through solids or generally speaking, facts about how do they interact with the real world.

So far I've found this nice calculator which comes really handy to understand which percentage of X-rays at a certain keV will pass thru (http://web-docs.gsi.de/~stoe_exp/web_programs/x_ray_absorption/) and probably answers all my needs about attenuation, however I would also like to know how good/bad do they reflect off metallic surfaces in a lab setting, so that apart common sense I could guess what are the chances of X-rays entering from a slightly opened shielded door (left in that way by hasty colleagues) performing a radiograph in the next room onto a flat table.
Do they infiltrate into gaps like fluids or more likely bounce in straight lines like visible light?
Considering the same generator energy, would increasing mA (photon flux) for a certain time also increase image noise, or would it be equal to a lower photon flux in a longer time (so that mA * time yield the same result in both cases)?

Thank you

Allison
 

Answers and Replies

  • #2
Simon Bridge
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Do they infiltrate into gaps like fluids or more likely bounce in straight lines like visible light?
Bouncey.

Bottom line: x-rays are a kind of light, so follow the same rules as for visible light.
All light can shine through a certain thickness of material, depending ont he material, for instance.
The brighter the light, the farther it travels in material, and also the more energetic the light ... so blue light is more penetrating than red.
Some materials are particularly good at absorbing some wavelengths though ... ruining the rule of thumb above.

I would also like to know how good/bad do they reflect off metallic surfaces in a lab setting...
http://universe.gsfc.nasa.gov/xrays/MirrorLab/xoptics.html

Considering the same generator energy, would increasing mA (photon flux) for a certain time also increase image noise, or would it be equal to a lower photon flux in a longer time (so that mA * time yield the same result in both cases)?
It's much the same idea as shining a brighter light on something.
 
  • #3
29
1
Bouncey.

Bottom line: x-rays are a kind of light, so follow the same rules as for visible light.
All light can shine through a certain thickness of material, depending ont he material, for instance.
The brighter the light, the farther it travels in material, and also the more energetic the light ... so blue light is more penetrating than red.
Some materials are particularly good at absorbing some wavelengths though ... ruining the rule of thumb above.


http://universe.gsfc.nasa.gov/xrays/MirrorLab/xoptics.html

It's much the same idea as shining a brighter light on something.

I see thank you. I've read that while following the same rules of visible light, they reflect a lot less, how true is this?

Thank you for the links
 
  • #4
Simon Bridge
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The more energetic the light, the further it may penetrate a material before being reflected or absorbed.
Also: Just like different colors of visible light may be reflected differently (which is roughly how objects get their color), so different wavelengths get reflected differently. The determining factor is how the electrons (or other charges) are arranged in the material.
You will have noticed that not all materials reflect visible light.
The same goes for light that is not visible.
 
Last edited:
  • #5
29
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I see, now it makes sense, thank you very much!
 

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