Noise in structure factor

Hi,

I’m conducting the all-atomistic simulation, and I calculated the structure factor.

At first, I calculated the structure factor using “saxs”, but there was a weird sharp high peak near 0, as shown in the figure below.

Thus, we tried to use the other tool, and used our own structure factor calculation tool using MDAnalysis, but it provided noisy and strange sharp peaks below 0.5, as shown in two figures below. They are from the same data, but displaying types are different: one is scatter and other is the plot.


Can you advise this phenomenon?