[HN Gopher] X-ray laser will 'film' chemical reactions in unprec... ___________________________________________________________________ X-ray laser will 'film' chemical reactions in unprecedented detail Author : gmays Score : 56 points Date : 2023-09-19 18:35 UTC (4 hours ago) (HTM) web link (www.nature.com) (TXT) w3m dump (www.nature.com) | easythrees wrote: | Dumb question here, but can X-Ray lasers be used to make CPUs? | itishappy wrote: | That's not a dumb question at all! They're next in line, but | there's a long road ahead! | | Modern EUV lithography uses 13.7nm light, barely shy of the | 10nm cutoff for X-Rays (and that's debatable). Many of the | problems we'll need to solve are already in-play with EUV | lithography, but with X-Rays they will be turned up to 11. | Directing the light is a huge one, most materials are | transparent to X-Rays so lenses aren't going to work, and | mirrors are difficult. Building an EUV or X-Ray mirror requires | coating stacks tens to hundreds of nano-meter thick layers | thick but still can't manage very high reflectivity. Also, at | these energies, the light easily ionizes substrate atoms | knocking electrons out which travel around and affect nearby | atoms, causing weird non-local stochastic effects. | | We've barely started EUV production, there's plenty of room for | optimization, so I'd bet we're decades away from using X-Rays | commercially, but you better believe we're trying! | | https://www.asml.com/en/products/euv-lithography-systems | | https://www.sciencedirect.com/topics/engineering/x-ray-litho... | benjaminva wrote: | Filming is one really interesting application, the other is | imaging of single proteins without the need for crystallisation. | I wrote a whole PhD thesis about the idea how to reconstruct the | three-dimensional electron density from a lot of extremely noisy | single proteins shots. It will make a huge class of proteins | experimentally accessible that we couldn't structurally look into | before. | pfdietz wrote: | Hasn't cryoelectron microscopy pretty much taken over for | protein structure determination? | eslaught wrote: | I don't work on this directly, but I do adjacent stuff in the | computer science research group at SLAC. | | Feel free to ask me questions, I guess? (I will not be able to | say much about the physics.) | MaxikCZ wrote: | Neat! Wouldnt powerful xrays change the reaction to be filmed? | eslaught wrote: | Again, not a physicist. But my understanding is that on a | femptosecond timescale (the duration of the x-ray pulse | generated by LCLS-II), effectively no reactions occur. The | pulse destroys the sample, so that means you have to pump | through a steady stream of sample particles to image. So for | any given experiment, you'll get a stream of what are | effectively snapshots of the reaction occurring at a given | moment in time, and then it's up to software post-processing | to figure out what you're looking at in a given snapshot and | how far progressed the chemical reaction is at that point. | natechols wrote: | I helped with similar experiments at LCLS-I and the first | half of this comment is correct. The chemical reaction is | carefully timed on the order of milliseconds, so they get a | series of snapshots of the reaction at a specific known | state (but previously unknown structure). There isn't | enough information in individual snapshots for the | processing software to do very much with besides combine it | with other snapshots (thousands of them). | itishappy wrote: | Incredible stuff. I can't imagine the undulators are perfectly | efficient at extracting all the energy from the electron beams. | What do you guys do with the leftovers? ___________________________________________________________________ (page generated 2023-09-19 23:00 UTC)