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A comment on Successful second round of fusion experiments with Wendelstein 7-X. Parent comment

Re:Successful second round of fusion experiments with Wendel... by ben_w on Monday November 26, 2018 @12:14PM (#18534879)
I doubt that. High energy neutrons are difficult to diffract (so no lenses), reflect more like light on fog than light on tin foil (so no mirrors) and pass through material too easily for a pinhole lens to be plausible.

I think you have to go to quite low energies (per neutron, not flux) for neutron optics to be a thing. Neutron cameras use collimated neutron sources to get around this, but that option isn’t available here: https://en.m.wikipedia.org/wiki/Neutron_imaging#Neutron_came...

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Re:Successful second round of fusion experiments with Wendel... by nine_k on Monday November 26, 2018 @12:24PM (#18534989)
You don't need to diffract the neutron flux. Instead, you can wrap (low-res) neutron-sensitive material around the stellarator tube. IDK now well would conventional photodiode or CCD work under high magnetic field, though.
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Re:Successful second round of fusion experiments with Wendel... by jessriedel on Monday November 26, 2018 @12:29PM (#18535038)
That would just record the total neutron flux. It won't form an image unless you have a lens, aperture, or something similar.
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Re:Successful second round of fusion experiments with Wendel... by nine_k on Monday November 26, 2018 @12:53PM (#18535295)
It's almost as if you posit that the flux through every piece of surface is exactly the same. I suspect it's not.
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Re:Successful second round of fusion experiments with Wendel... by jessriedel on Monday November 26, 2018 @07:23PM (#18538130)
No, total flux at a given location, not total flux in the whole device. The point is that it doesn't identify which direction the neutrons are coming from. That's why lens or apertures are needed.
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