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Lei Wang
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Hi, guys. Did you ever encounter the problem of X-ray disappearing caused by size effect?
What does one mean by 'X-ray disappearing'? Size of what?Lei Wang said:Hi, guys. Did you ever encounter the problem of X-ray disappearing caused by size effect?
Is one referring to X-ray diffraction? Or is one referring to generating characteristic X-ray by electron bombardment?Lei Wang said:Hi, thanks.
I am doing some research about nano porous materials. The bulk materials, I can get a X-ray peak for each element. But when I made it into nano porous material, the peak is gone. The same thing happened to my teammates. In one word, we can't get X ray for a nano-porous material.
Dave_H said:The width of your peak is a function of several things, including grain size, and residual stress/strain (sample prep, thermal strain...). Are your raw materials nano-structured? Or are you using a insitu grain-refinement technique? If your are losing your peaks due to grain refinement try scanning the angle where you know the peaks should be, but very slowly to try and increase the number of counts, sometimes this will make it easier to distinguish a very low height, high width peak, from the background. I just worked on this today, so I'll attach a figure displaying what I mean.
I hope this helps.
The "size effect" refers to the phenomenon of reduced X-ray intensity or disappearance of X-ray signals when a sample size decreases below a certain threshold. This is due to the fact that smaller sample sizes have a lower number of atoms, resulting in a weaker signal.
The size effect occurs due to the decrease in the number of atoms present in a smaller sample. X-rays interact with the electrons in the atoms, and when there are fewer atoms, the signal becomes weaker or may disappear completely.
The size effect can be identified by a sudden decrease or disappearance of X-ray signals when the sample size is reduced. This can be observed through changes in the X-ray diffraction pattern or X-ray fluorescence intensity.
The size effect can be caused by a variety of factors, including changes in sample density, surface roughness, and sample positioning. It can also be influenced by the type of X-ray technique used and the properties of the sample material.
To mitigate the size effect, it is important to carefully consider the sample preparation and measurement techniques. This can include using a larger sample size, adjusting the sample positioning, and optimizing the X-ray technique settings. Additionally, using a reference sample of known size and composition can help to correct for the size effect.