Table-top 'mini-LHC' ramps up to record energy

[jwl]

TABLE-TOP particle accelerators can now rival the real thing. A laser-powered device just centimetres long can boost electrons to energies previously seen only in giant smashers.

The world's biggest accelerator, the Large Hadron Collider at CERN near Geneva, Switzerland, is a 27-kilometre ring that next year will slam particles together at energies of 13 teraelectronvolts (see "2015 Preview: Rebooting the particle smasher"). But even standard-size facilities require tunnels hundreds of metres long to reach gigaelectronvolt (GeV) energies.

Physicists have been working to develop accelerators that could run on an ordinary lab bench. Now Wim Leemans of the Lawrence Berkeley National Laboratory in California and his colleagues have got particles in their 9-centimetre-long device up to 4.2 GeV (Physical Review Letters, doi.org/xpr).

The trick is to use a high-powered laser pulse to create waves in a plasma, which electrons can ride like surfers. The team were able to better control their waves than in previous table-top accelerators, letting them build a longer tube and thus reach higher energies. More advanced lasers are needed to sustain the pulses before big facilities can be replaced, says Leemans.

http://www.newscientist.com/article/mg2 ... VJQEt14gKA
Paper:

ABSTRACT
Multi-GeV electron beams with energy up to 4.2 GeV, 6% rms energy spread, 6 pC charge, and 0.3 mrad rms divergence have been produced from a 9-cm-long capillary discharge waveguide with a plasma density of ≈7×1017  cm−3, powered by laser pulses with peak power up to 0.3 PW. Preformed plasma waveguides allow the use of lower laser power compared to unguided plasma structures to achieve the same electron beam energy. A detailed comparison between experiment and simulation indicates the sensitivity in this regime of the guiding and acceleration in the plasma structure to input intensity, density, and near-field laser mode profile.

http://dx.doi.org/10.1103/PhysRevLett.113.245002
No preprint I think, unfortunately.

[LaCroix]

Cool!

So, knowing how minds work - how long until we'll see a first prototype of a weaponized particle accelerator?

I know, a single particle with 4GeV would be a 10-10 Joule, but once you use it to send a mol of something downrange, it would add up, I guess.
I just don't know how much range such a particle beam would have.

[Alyrium Denryle]

Cool!

So, knowing how minds work - how long until we'll see a first prototype of a weaponized particle accelerator?

I know, a single particle with 4GeV would be a 10-10 Joule, but once you use it to send a mol of something downrange, it would add up, I guess.
I just don't know how much range such a particle beam would have.

6.002x10^13 joules, in point of fact
6.002x10^10 kilojoules'
6.002x10^7 megajoules
6.002x10^4 gigajoules
or
60.02 Terajoules. Or... Hiroshima.

As for range, the energy would drop off with beam scattering as particles collide with other particles. Some application of the N^2 law would apply, but I dont know the coefficient.

[LaCroix]

Cool!

So, knowing how minds work - how long until we'll see a first prototype of a weaponized particle accelerator?

I know, a single particle with 4GeV would be a 10-10 Joule, but once you use it to send a mol of something downrange, it would add up, I guess.
I just don't know how much range such a particle beam would have.

6.002x10^13 joules, in point of fact
6.002x10^10 kilojoules'
6.002x10^7 megajoules
6.002x10^4 gigajoules
or
60.02 Terajoules. Or... Hiroshima.

As for range, the energy would drop off with beam scattering as particles collide with other particles. Some application of the N^2 law would apply, but I dont know the coefficient.

Wowzers... With that kind of energy burning a path through atmosphere, it'd be a quite visible effect. I'd guess it would look like lightning, right?

[NoXion]

Rather than weapons, I was thinking what we might be able to discover if we could combine the power of these new accelerators with the size of the old facilities. Enough perhaps to reach the energies needed to experimentally test things like string theory?

[jwl]

Wowzers... With that kind of energy burning a path through atmosphere, it'd be a quite visible effect. I'd guess it would look like lightning, right?

Something like a cosmic ray I imagine.


(Obviously the earth bit is superimposed, but the cosmic rays were probably taken with a gamma telescope or simulated).

[Irbis]

Rather than weapons, I was thinking what we might be able to discover if we could combine the power of these new accelerators with the size of the old facilities. Enough perhaps to reach the energies needed to experimentally test things like string theory?

It's kind of like asking 'what if we made a bike the size of train'. It would be pointless because the shape is dictated by outside factors and would do little applied to another device.

I guess we can make lasers powerful enough to eventually replicate LHC, but LHC features controlled collisions where we want them. Laser device seems to function like a bomb - detonate target and hope it will do something useful. I am not even sure if higher energy laser won't simply produce too many too energetic random collisions blinding detectors.

So, knowing how minds work - how long until we'll see a first prototype of a weaponized particle accelerator?

Why bother?

Laser they used for it will be much easier to weaponize, smaller, and easier to use than the whole device. While "electron ray gun" sounds cool, beta particles can be probably easily stopped by ceramic or aluminium plates in normal ballistic vest, unless unusually energetic.

[LaCroix]

So, knowing how minds work - how long until we'll see a first prototype of a weaponized particle accelerator?

Why bother?

Laser they used for it will be much easier to weaponize, smaller, and easier to use than the whole device. While "electron ray gun" sounds cool, beta particles can be probably easily stopped by ceramic or aluminium plates in normal ballistic vest, unless unusually energetic.

Rule of cool. We are a sci-fi forum, after all...

First, I wasn't aware if a particle beam would fare better or worse in atmosphere than a laser would.
And second, didn't somebody mention (again and again) that a particle beam hitting a solid object doesn't necessarily need to penetrate the target, but still would be very, very bad just due to ionization?

[Executor32]

Cool!

So, knowing how minds work - how long until we'll see a first prototype of a weaponized particle accelerator?

I know, a single particle with 4GeV would be a 10-10 Joule, but once you use it to send a mol of something downrange, it would add up, I guess.
I just don't know how much range such a particle beam would have.

6.002x10^13 joules, in point of fact
6.002x10^10 kilojoules'
6.002x10^7 megajoules
6.002x10^4 gigajoules
or
60.02 Terajoules. Or... Hiroshima.

As for range, the energy would drop off with beam scattering as particles collide with other particles. Some application of the N^2 law would apply, but I dont know the coefficient.

Wowzers... With that kind of energy burning a path through atmosphere, it'd be a quite visible effect. I'd guess it would look like lightning, right?

Perhaps a little something like this?



I mean, when I see the words 'weaponized particle accelerator', thats the first thing I think of.

[Sky Captain]

My guess is particle beam weapon would be of very short effective range when used inside atmosphere. At least to a laser light of right frequency atmosphere is more or less transparent while particles from particle beam weapon would immediately start colliding with air molecules and scatter degrading the beam quality very quickly. IIRC all real proposals for particle beam weapons were for use in vacuum to fry electronics of incoming enemy ICBM warheads

[NoXion]

It's kind of like asking 'what if we made a bike the size of train'. It would be pointless because the shape is dictated by outside factors and would do little applied to another device.

What are these unspecified "outside factors"? I thought we were talking about accelerating particles here, objects rather unlike bikes and trains, which are macroscopic and capable of accelerating under their own power. So I don't understand the analogy you're making here.

I guess we can make lasers powerful enough to eventually replicate LHC, but LHC features controlled collisions where we want them. Laser device seems to function like a bomb - detonate target and hope it will do something useful. I am not even sure if higher energy laser won't simply produce too many too energetic random collisions blinding detectors.

Lasers are nothing like bombs. For a start, the energy in a laser travels in one direction, unlike a bomb which disperses energy in all directions.

[Sea Skimmer]

Rule of cool. We are a sci-fi forum, after all...

First, I wasn't aware if a particle beam would fare better or worse in atmosphere than a laser would.
And second, didn't somebody mention (again and again) that a particle beam hitting a solid object doesn't necessarily need to penetrate the target, but still would be very, very bad just due to ionization?

Most forms of particle beam are completely useless in the atmosphere, though they have great long term promise as space to space weapons. A weaponized particle accelerator is more or less what a free electron laser is though. The biggest advantage is not in raw power or penetrating power, but rather the ability of the particle accelerator to adjust its beam form in real time to compensate for atmospheric effects, providing far higher effective ranges at high power. Also a single particle accelerator could be piped to multiple beam directors in principle.

For the moment we could expect a FEL to deliver a lot more raw power then any other form of electrically powered laser, and on par with chemically powered lasers, but that's an advantage that probably won't be true by the time a FEL could be ready for field service in the 2020s or later. The tuning ability though just can't be done in other forms of lasers.

Downside is all particle accelerator tech as we know it requires supercooling, supercooling that takes ~ 2 days to be effective from room temp. That isn't as big a deal for space where the refrigeration cost is trivial, but on a ship or land based system it means if you have to turn the sucker off to maintain it or save energy you aren't getting it back online quickly.

[Simon_Jester]

It's kind of like asking 'what if we made a bike the size of train'. It would be pointless because the shape is dictated by outside factors and would do little applied to another device.

What are these unspecified "outside factors"? I thought we were talking about accelerating particles here, objects rather unlike bikes and trains, which are macroscopic and capable of accelerating under their own power. So I don't understand the analogy you're making here.

The most likely explanation is that Irbis thinks there is some aspect to the laser-plasma acccelerator that would not scale well.

Bicycles are the size they are because they are vehicles designed to carry one person (or maybe two or three), designed to be pedaled by humans. If you made one the size of a train then either it wouldn't be safe, or it wouldn't go anywhere, or it wouldn't be recognizable as anything like a bicycle. Or some combination of the above.

So Irbis is probably arguing that elements of the laser-pumped plasma system would not work well if scaled up to weapon-level energies. I imagine so, anyway; otherwise his argument doesn't make much sense.

Whether he is right or wrong, I could not say.

[jwl]

Laser device seems to function like a bomb - detonate target and hope it will do something useful. I am not even sure if higher energy laser won't simply produce too many too energetic random collisions blinding detectors.

Isn't it exactly the same with the LHC, since they use protons rather than electrons and thus get a ton of random useless stuff when they collide?

Laser they used for it will be much easier to weaponize, smaller, and easier to use than the whole device. While "electron ray gun" sounds cool, beta particles can be probably easily stopped by ceramic or aluminium plates in normal ballistic vest, unless unusually energetic.

I think 4.2 GeV counts as "unusually energetic". That's 4-5 times the mass energy of a proton. In an electron.

And second, didn't somebody mention (again and again) that a particle beam hitting a solid object doesn't necessarily need to penetrate the target, but still would be very, very bad just due to ionization?

I dunno about ionization, but regardless of whether it penetrates anywhere, the you're going to get a ton of X-rays due to relativistic bremsstrahlung, and that's going to penetrate stuff.

Bicycles are the size they are because they are vehicles designed to carry one person (or maybe two or three), designed to be pedaled by humans. If you made one the size of a train then either it wouldn't be safe, or it wouldn't go anywhere, or it wouldn't be recognizable as anything like a bicycle. Or some combination of the above.

So Irbis is probably arguing that elements of the laser-pumped plasma system would not work well if scaled up to weapon-level energies. I imagine so, anyway; otherwise his argument doesn't make much sense.

Whether he is right or wrong, I could not say.

In the new scientist article above, it says:

The trick is to use a high-powered laser pulse to create waves in a plasma, which electrons can ride like surfers. The team were able to better control their waves than in previous table-top accelerators, letting them build a longer tube and thus reach higher energies.

So yeah, there are difficulties with scaling it up.

[Simon_Jester]

Laser device seems to function like a bomb - detonate target and hope it will do something useful. I am not even sure if higher energy laser won't simply produce too many too energetic random collisions blinding detectors.

Isn't it exactly the same with the LHC, since they use protons rather than electrons and thus get a ton of random useless stuff when they collide?

Uh, you get random useless stuff either way. The main difference is that in a conventional accelerator you have quite precise control over the exact energies involved and precisely where the beam goes. Decreasing this control has drawbacks.

Laser they used for it will be much easier to weaponize, smaller, and easier to use than the whole device. While "electron ray gun" sounds cool, beta particles can be probably easily stopped by ceramic or aluminium plates in normal ballistic vest, unless unusually energetic.

I think 4.2 GeV counts as "unusually energetic". That's 4-5 times the mass energy of a proton. In an electron.[/quote]Extremely high energy beta particles like this are a few orders of magnitude more energetic than the ones normally released by nuclear decay processes, so there's that.