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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Thanks for your answer, Steve.<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">One clarification: By specimen thickness I meant actual protein thickness, for example 2 layers of catalase rather than 1,<br>
or a long cylindrical molecule in top view rather than side view.<br>
Wouldn’t that lead to a big difference in percent amplitude contrast if amplitude contrast is due to multiple scattering?<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">Från:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Ludtke, Steven J [mailto:sludtke@bcm.edu]
<br>
<b>Skickat:</b> den 15 augusti 2017 14:48<br>
<b>Till:</b> Philip Koeck<br>
<b>Kopia:</b> Sacha De Carlo; 3dem@ncmir.ucsd.edu<br>
<b>Ämne:</b> Re: [3dem] [TEM] amplitude contrast<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">If it’s due to multiple scattering, it must depend strongly on specimen thickness.</span><span lang="EN-US"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">If it’s due to inelastic scattering, why is it so weak (about 10%)? Inelastic scattering has a larger cross section than elastic, I believe.</span><o:p></o:p></p>
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<p class="MsoNormal">Clearly the attenuation of the beam is impacted strongly by specimen thickness. However, the effect you are referring to as amplitude contrast is due to the difference in scattering in one part of the specimen vs another. That is, uniform
solvent added above or below the feature producing contrast simply attenuates the beam uniformly, and doesn't produce "contrast".<br>
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