[HN Gopher] Particle accelerators for the microchip era
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       Particle accelerators for the microchip era
        
       Author : sharpshadow
       Score  : 104 points
       Date   : 2024-06-04 19:39 UTC (1 days ago)
        
 (HTM) web link (www.moore.org)
 (TXT) w3m dump (www.moore.org)
        
       | PeterCorless wrote:
       | I've known Dr. Byer for years and years. A great guy. So glad
       | that he and his team at Stanford are getting due recognition for
       | this work.
        
         | thenobsta wrote:
         | Agreed, he's an amazing man. He was on my Qualifying Exam
         | committee....and I presented on dielectric laser accelerators.
         | Apparently I didn't butcher it.
         | 
         | I'm glad the effort is progressing and getting recognition! It
         | would be really cool to see a lot of microfabricated
         | accelerators out in the wild. There are lots of applications
         | for these things and it would unlock a lot of value for the
         | world.
        
           | mensetmanusman wrote:
           | Any startups trying to commercialize these?
        
             | thenobsta wrote:
             | Not that I know of. I was adjacent to this work about 9yrs
             | ago but have tracked it since. The technology is still too
             | early and too risky to work on commercializing. Amazingly
             | though, one of the lowest energy (read easiest, but still
             | hard. The technology is not there yet.) applications is for
             | use as a targeted radiation source for cancer therapies.
             | This paper[0] covers that a little bit and offers a few
             | other applications. I recall seeing a paper that proposed
             | different applications at different energy levels. I'll see
             | if I can dig it up.
             | 
             | [0] https://www.slac.stanford.edu/pubs/slacpubs/16750/slac-
             | pub-1...
        
       | pmayrgundter wrote:
       | The continued shrinking of accelerators has had me brainstorming
       | on a compact nanofusion approach for awhile
       | 
       | https://docs.google.com/document/d/1B5maRx9w0ahQTqSe6UZ56rd0...
        
         | ben_w wrote:
         | You might want to also look at what can already be done with an
         | electrostatic design such as a fusor, and why they _aren 't_
         | widespread outside of science fair projects.
         | 
         | Another limitation with anything micro-fabricated is that the
         | resulting radiation from fusion working is going to knock atoms
         | out of their lattices, degrading chips in direct proportion to
         | total (lifetime) energy output.
        
       | ooterness wrote:
       | No information on what kind of energy levels these can achieve?
       | i.e., keV or MeV?
        
         | PeterCorless wrote:
         | "Using a more sophisticated silicon structure, still for
         | subrelativistic electrons (96.3 keV), the highest gradient
         | achieved is 370 MV/m over a 5.4 mm interaction length in the
         | dual pillar silicon structure with two-sided illumination"
         | 
         | -- Source:
         | https://opg.optica.org/oe/fulltext.cfm?uri=oe-30-1-505&id=46...
        
           | baq wrote:
           | I heard about photon rockets, I heard about ion drives, but
           | an electron rocket motor is new. Can't be bothered to do the
           | math here but Isp doesn't sound too bad eyeballing it...? 1
           | eV is 5.94 x 10^6 m/s but multiplying this by 96.3k looks
           | like it needs a relativistic correction.
        
         | photochemsyn wrote:
         | "These on-chip devices accelerate sub-relativistic electrons of
         | initial energy 83.4 keV by 1.21 keV over 30 mm, providing peak
         | acceleration gradients of 40.3 MeV/m." (Sapra et al. Science
         | 2020)
         | 
         | Lasers on a chip plus photonic waveguide technology, oh my!
         | 
         | https://arxiv.org/pdf/1905.12822
         | 
         | [edit this is an earlier version see other comment]
        
       | pfdietz wrote:
       | A problem with all these advanced acceleration techniques is beam
       | quality. I'd worry imperfections in the microfabricated device
       | would cause this to degrade. Imperfections become increasingly
       | important as the device is miniaturized; in a 1 micron device, an
       | offset of a single atom's width is .01%.
        
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