Measuring your photons

X-rays are incident on a sample and then they bounce off, because of their coherent incidence it means that some scattered X-rays add together and others cancel out and we call this diffraction. But the key thing it means is that there are not X-rays everywhere only at allowed angles relative to the surface and in the case of single crystals as we have here at Diamond only in particular directions as well.

A simple 1D version of X-ray Diffration

So imagine a sphere around your sample (which is illuminated by your X-rays) and if you were to look around on the surface of that sphere only at distinct spots would you observe any X-rays scattered from the sample. This makes measuring the X-rays an initial mental calculation as to where to look in 3D space where you have control over the x, y, z, rotation around x, rotation around y and rotation around z of the sample and then motion of the detector in polar co-ordinates with a fixed r value centred around your sample.
So far too many compound motions translated into reciprocal space with very distinct peak intensity locations, our very own version of a needle in a haystack.
I'm sure this sounds all nice and complicated I unfortunately could not find a clear diagram, so I will have to make one. Watch this space (after lunch) as a photo of the actual kit is somewhat confusing without being able to look round it.

Photo of the set up