X-Ray crystallography using Bragg's Law

Question

I was looking up X-Ray crystallography using Bragg's Law:

$2d\sin\theta = n\lambda$

and I can understand the values of everything except this integer value $n$.

As far as my research got $n$ is used to describe the atom spacing in the crystal lattice, but I don't understand how you'd express $n$ or how it would describe it.

Could someone please explain this to me please?

Note: diagrams tend to be very useful in developing my understanding and if anyone has any reference to a video that might help as well. Thanks.

Answer 1

EDIT:

I was wrong. The problem is as follows:

You can get several peaks for the same plane ($n=1$ peak, $n=2$ peak etc.). So if you, after measuring angles and making calculations, get plane distances $d$ and $\frac{d}{2}$, $\frac{d}{2}$ is just $n=2$ peak and $d$ is $n=1$ peak of the same set of diffraction planes.

Also, here is good explanation:

http://www.bruker-axs.de/fileadmin/user_upload/xrfintro/sec1_8.html

Answer 2

Positive interference occurs when the waves reflected from two different "layers" differ by an (any!) integer number of wavelengths: $n$ is that integer.