How much can affect (in terms of hump) my X-ray diffraction pattern the "amorphous" glass or maybe someone can suggest me other material to compensate for the small amount of the sample. Note: my sample is a powder.
In the days when I did this sort of thing I used to use silica powder. Yes, you do get a smoothly curved background, but this is easy to seperate from the sharp diffraction lines. I could even get lines from materials adsorbed onto silica powder where the ratio of sample to silica was well below 1:100.
I'm assuming your sample is crystalline - if your sample is amorphous as well I'm afraid you have a problem.