[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)