Is Bragg Diffraction Depicted Accurately in Common Diagrams?

In summary, the conversation discusses the concept of Bragg diffraction in acousto-optics and whether the angle of incidence and reflection should be equal in a perfect case. The speaker presents a picture that contradicts this idea, but acknowledges that X-ray crystallography still works as long as the Bragg criterion is satisfied. Another picture is brought up showing equal angles, causing confusion for the speaker. The conversation ends with the conclusion that the diagram may be incorrect.
  • #1
2sin54
109
1
Hi. So I am studying a bit on acousto-optics and as far as I've gathered, when the Bragg condition is met, the incident ray of light should just be reflected (in a perfect case) with the angle of reflection equal to the angle of incidence.
However, this picture does not agree with my thoughts: http://www.mt-berlin.com/pict_0/fig1ao.gif

Is it correct? I mean the Bragg diffraction. The picture clearly suggests that the incidence and reflection angles need not be equal..
 
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  • #2
Gytax said:
Hi. So I am studying a bit on acousto-optics and as far as I've gathered, when the Bragg condition is met, the incident ray of light should just be reflected (in a perfect case) with the angle of reflection equal to the angle of incidence.
However, this picture does not agree with my thoughts: http://www.mt-berlin.com/pict_0/fig1ao.gif

Is it correct? I mean the Bragg diffraction. The picture clearly suggests that the incidence and reflection angles need not be equal..
If they were always equal, I think that X Ray crystallography would not work. All that's necessary is for the Bragg criterion to be satisfied.
 
  • #3
sophiecentaur said:
If they were always equal, I think that X Ray crystallography would not work. All that's necessary is for the Bragg criterion to be satisfied.
Hmm, but there's plenty of pictures like these: http://skuld.bmsc.washington.edu/~merritt/bc530/bragg/index_files/BraggDeriv.gif . They seem to suggest that the angles are in fact equal. I am really confused right now.
 
  • #4
Can you not get different orders for the incoming and outgoing beam? Perhaps not. The Bragg equation doesn't suggest that you can.
The most likely answer is that the diagram you are looking at is just drawn wrong.
 

1. What is Bragg diffraction?

Bragg diffraction is a phenomenon in which X-rays or other electromagnetic radiation are diffracted by the regularly spaced atomic planes in a crystal lattice. It is named after the father-son duo of physicists, William Henry Bragg and William Lawrence Bragg, who first described this effect in 1913.

2. How does Bragg diffraction work?

Bragg diffraction occurs when X-rays or other electromagnetic radiation interact with atoms in a crystal lattice. The atoms act like tiny scattering centers, causing the radiation to be diffracted in different directions. The spacing between the atoms in the crystal lattice determines the angle at which the radiation is diffracted, and this can be measured to determine the structure and spacing of the atoms in the crystal.

3. What is the Bragg equation?

The Bragg equation is a mathematical equation that relates the angle of diffraction to the wavelength of the radiation and the spacing between the atomic planes in a crystal lattice. It is given by nλ = 2d sinθ, where n is the order of diffraction, λ is the wavelength of the radiation, d is the spacing between atomic planes, and θ is the angle of diffraction.

4. What are some applications of Bragg diffraction?

Bragg diffraction has numerous applications, including determining the structure of crystalline materials, such as minerals and proteins, in materials science and biology. It is also used in X-ray diffraction techniques for studying the atomic structure of materials, and in X-ray crystallography for determining the structure of molecules.

5. How is Bragg diffraction different from regular diffraction?

Bragg diffraction is a type of diffraction that occurs specifically in crystalline materials, where the atoms are arranged in a regular, repeating pattern. In regular diffraction, the diffracting object does not need to have a regular structure, and the diffracted waves can have different wavelengths. In Bragg diffraction, the diffracted waves must have the same wavelength, and the angle of diffraction is determined by the spacing of the atomic planes in the crystal lattice.

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