
Particle accelerator fits on the head of a pin - rbanffy
https://techcrunch.com/2020/01/02/this-particle-accelerator-fits-on-the-head-of-a-pin/
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knzhou
From the standpoint of particle physics, these aren’t that exciting. Though
you would never know it from the article, the electric fields in these things
are about the same as the fields in existing accelerators, because they’re
both limited by the fact that strong fields start ripping the thing apart. So
they wouldn’t actually “shrink” particle accelerators at all. They’re 1,000
times smaller than the existing cells, but you would need 1,000 times more of
them to get the same effect.

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not2b
The intended application isn't particle physics: "These won’t be rivaling
macro-size accelerators like SLAC’s or the Large Hadron Collider, but they
could be much more useful for research and clinical applications where planet-
destroying power levels aren’t required. For instance, a chip-sized electron
accelerator might be able to direct radiation into a tumor surgically rather
than through the skin."

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TeMPOraL
So that's a step towards particle weapons, right? :).

I'm only half-joking here. In my copious spare time, I sometimes wonder how
one could approach building something resembling a phaser. The most recent
question I've added to my "to investigate" list is, is there a way of sending
energy (either as photons or via larger particles) that would avoid scattering
off targets? Scattering is a problem with lasers - if you take one that's
powerful enough to be interesting and use it in enclosed space, you'll get
everyone in the room not wearing eye protection blind before the target starts
to heat up.

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rbanffy
A particle canon that can accelerate a gas with good directional control (that
can be aimed and focused) with sufficient energy to cause damage to an object
5m away will probably be better applied as deep space propulsion than as a
weapon.

It's a bit like a space invasion - if you plan on invading another planet,
just accelerate for the first part of the trip, point the engine to the
destination and fire it for the rest of the trip. When you arrive, there will
probably be no armies, of lifeforms, to resist you.

OTOH, you may need to wait a couple million years before the planet is cool,
or inhabitable again.

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ericjang
Might be simpler just to accelerate a small un-crewed ship to approach the
speed of light, and strike the planet with it as a kinetic weapon (causing an
extinction event but not enough to actually disintegrate the planet). Closely
following behind can be a slower ship containing the colonizing party. Then
there won't be a need to heat up the target planet.

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rbanffy
1\. Throw out the garbage before hitting the brakes.

2\. Garbage hits planet at relativistic speed.

3\. Profit.

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AllegedAlec
> Sapra et al. developed an integrated particle accelerator using photonic
> inverse design methods to optimize the interaction between the light and the
> electrons. They show that an additional kick of around 0.9 kilo–electron
> volts (keV) can be given to a bunch of 80-keV electrons along just 30
> micrometers of a specially designed channel.

A lot less exiting than techcrunch says, but I wouldn't know why I expected
better.

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cosmic_quanta
The exciting part of this is the gradient. The addition of 1keV in 30um is
huge!

For reference, in a typical electron microscope, accelerating fields might
reach a 1 MeV/m gradient. In these cases, it's usually an anode (-200kV) and
cathode (0V) closely separated. High vacuum is required, it's large, power
supplies are enormous, etc.

Scaling the results of this paper, especially after a working prototype, will
be more interesting to the general population. But the key discoveries are
already here. Scaling becomes an engineering concern.

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jandrese
Is there any reason they couldn't chain a whole bunch together to kick up to
higher energy levels? Say you need 50um per segment for the support framework
and whatnot, you could pack 200 of them in a cm long instrument and kick up
the power by 200keV?

~~~
cosmic_quanta
Oh yes, that's what I would anticipate.

The design shown in this paper is specific to an initial electron energy of
83keV. That means that chaining identical parts wouldn't work, but you could
have an array of similar parts with slightly different properties at each
"stage".

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baq
two questions immediately coming to mind:

1\. can one build a viable rocket engine out of an array of these? if it runs
on IR, can one reuse the heat it generates to improve its own efficiency?

2\. can one build a handheld/mounted particle beam weapon with these?

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selimthegrim
This was done for molecular beams too, at MPI Göttingen and FHI some years
ago.

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deckar01
Original paper: [https://sci-
hub.se/https://doi.org/10.1126/science.aay5734](https://sci-
hub.se/https://doi.org/10.1126/science.aay5734)

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shmageggy
Anyone have a non-Verizon source? I refuse to use a site with obfuscation and
anti-patterns in their privacy options.

