In solution phase X-ray there is a phenomena wherein photons scattered from the analyte are re-scattered from neighboring particles prior to reaching the instrument detector. During data analysis how to take care of this effect?
Dear Nita Ghosh ,
multiple scatter does not only take place in solution phase x-ray scattering, but in all X-ray scattering experiments.
However in geometries in which only surface near regions or short interaction length in the range of the attenuation lengths of the x-rays are involved the multiple scatter contributions to the detector signal can befortunately neglected.
This is due to the small coherent scatter cross section of x-rays compared to the total attenuation cross section and in case of incoherent scatter (Compton scatter ) due to the lossy scatter into nearly full 4pi space.
Dear Gerhard,
Thank you for your answer. Can you please provide some sources where I can a read more about this?
Dear Nita,
for example you may have a look here.
Article Multiple-scattering effects in SAXS and XPCS measurements in...
But, sorry, you have to request the full text.
Nevertheless it is stated in the abstract that in many cases the multiple scatter contribution can be 'tolerated'.
In
Article Everything SAXS: Small-Angle Scattering Pattern Collection a...
section '3.4.8 Multiple Scatter Corrections' at page 15 some precautions/correction procedures are advised for the case of 'a transmission factor below approximately 1/e' *). You may go through the mentioned literature therein.
The following papers do not explicitely deal with multiple scatter corrections but they could be interesting for you as well:
Article The modular small-angle X-ray scattering data correction sequence
Article The modular SAXS data correction sequence for solids and dispersions
*) 1/e transmission is achieved at one attenuation length, which I mentioned above.
A more sophisticated way to obtain isolates the scattering contributions is to analyze the trajectory of an MD simulation that most effectively captures the dynamics of your material system.
Once you can come up with an MD model that does so, you can computationally carry out the XPCS and extract an approximate signal. Here is a paper I've recently written to address the same: Preprint Computational Approaches to Model X-ray Photon Correlation S...
You can also check the computational XPCS code:https://gitlab.com/micronano_public/c-xpcs
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