We are building a Small Angle Light Scattering instrument in our lab where the scattering pattern is formed on a white printer paper screen. We changed the screen paper to a laminated white paper (and deducted the background) but saw that there was a difference in the 1D projection of the 2D scattering pattern obtained in both cases. (As can be seen from the attached image)
Is there a standard material that is typically used for the purposes of collecting the scattered image in SALS ? Are there standard screen materials for other kinds of scattering ?
Dear Uma, Your recording of sizes of scattering light spots shows a contradiction results about angular divergency of scattering beam that is why Your set right question about right screen for studying...Laminated paper works like bed waveguide by spreading scattering light in 2D direction due to TIR- effect. Regular paper is also partially spread incident beam and in the case of coherent laser beam additional effects like "speckle pattern" takes place. Shortly speaking, the best way in your case means to use beam with low coherence and, if it is possible to refuse from observation with screen anyway.
Any success!
If I understand you correctly, you put paper screen on the plane, where you like to register scattering distribution and then you made an image of this distribution. Is it correct?
If so, your result definitely will depends on scattering properties, indicatrice of your paper, which is illustrated by your data.
You can exclude paper indicatrice influence by completely removing your paper screen. Exchange it by lens, even simplest one, and create by it image of your object of study. Then you can put into plane of this image lens of webcam or other imaging camera and focus it on the plane of the first lens. In such layout you will measure your scattering distribution without influence of paper indicatrice. Additional gain of such layout is much higher sensitivity.
Dear Uma ...
there is many materials that they have same scattering of paper that u be used as we know ,so if we know the principle of the paper is wood ,so there is a lot of materials like silica and another materials ,but as we know there is no materials have no scattering but the consentration effectted on the scattaring so u can used materais whith lou consentration like aerogel and zerogel.....
@ Eugene A. Tikhonov Thank you very much for your suggestion. Unfortunately, we cannot remove the screen completely as we need to take the image at an angle while simultaneously recording the the counts using a photodiode.
@ Valeriy Sterligov Thank you for your suggestion, it was very helpful.
The way we overcame this problem is that we purchased a polystyrene coated imaging screen (https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=7489&pn=EDU-VS1) this screen has a non homogeneous rough surface, creating a non-q dependent scattering from the screen- if any.
Thanks again for replying.
We solved the issue by purchasing the screen from THorlabs(https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=7489) that has a polystyrene coating on it - it has q independent scattering.
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