Have you ever seen a virus?

I have in the aggregator a reference to the 'physics tao' that many time has interesting posts. Today we have available one about X-rays and virus. The resolution to see this really incredible little things is incredible. It seems to need really brilliant and coherent light, but a read of the referred article is mandatory.

Starting for the abstract, the words X-ray diffraction, increase my interest. Lest to read the complete article! Yes, it talks about Synchrotrons, about brilliant sources, cites the X-FEL, and the experiment was carried in Spring-8 (the highest electron energy synchrotron and the most brilliant x-ray source).


Did you ever meet a virus? It a really small organism and because of it length the light necessary to distinguish its parts has to be really energetic to see the structure a small distance detail.

In the article also has mention the effect of the radiation dose to the sample. Yes, the live structures doesn't like the radiation, but you need this light to see it. It seems a contradiction, but the way to do it is to reduce the exposition time that the sample has. A fast shutter is important, and now I understand better why I need to work for a ~1ms fast shutter for the NCD beamline. Reduce the exposition time of the sample to the x-rays to the exact time that the SAXS detector is available.

Uau! Here they talk about the improvement that can be the xfel use and a ultrafast pulses of <= 25 femtoseconds. This can allow more energetic dose during less time, but probably this relation is not linear. I say, more energy means much less time.