New Particle Collider Is One Foot Long

Jason Koebler writes The CERN particle collider is 17 miles long. China just announced a supercollider that is supposed to be roughly 49 miles long. The United States' new particle collider is just under 12 inches long. What the SLAC National Accelerator Laboratory's new collider lacks in size, it makes up for by using plasma to accelerate particles more than 500 times faster than traditional methods. In a recent test published in Nature, Michael Litos and his team were able to accelerate bunches of electrons to near the speed of light within the tiny chamber."

Comments

Not exactly

[Anonymous Coward]

If you read the article (damn you, paywall!) you note that this is essentially an afterburner, and does not start with stationary electrons. In this particular instance it requires a 2 km linear accelerator before the 12 inch magic booster box. 20 GeV electrons are accelerated by a further 1.6 GeV. Still interesting research, but definitely not what is claimed in the summary (surprise).

Re:Not exactly

[joe_frisch]

If you do a Google search on

SLAC PUB plasma wakefield
you will find a lot of non-paywalled papers on this and related plasma accelerator experiments at SLAC.

Re:Not exactly

[Chalnoth]

There's no problem in daisy chaining them, but I don't think you can guarantee the same energy boost each time. One of the big physics problems here is that accelerating charged particles radiate when they are accelerated, which acts as a sort of friction. The amount that is radiated increases quite dramatically as the particle gets closer to the speed of light (the energy loss scales as (E/(mc^2))^4). In practice, this means that if you dump a bunch of energy into an electron to accelerate it, you'll only add a fraction of that amount to its kinetic energy (the rest will be lost in radiation).

Given this, the naive expectation is that each subsequent box will add less and less to the energy of the particles. The disclaimer here is that I haven't studied the specific physics of plasma shock acceleration, so I don't know how such acceleration scales with energy. I do know, however, that this is the exact same mechanism that is suspected to be behind the "oh my god" particles (single particles with more than ten million times the energy that the LHC can produce): plasma shock fronts in the galaxy accelerate some small fraction of the interstellar protons to unbelievable speeds.

Re:Not exactly

[the gnat]

Yes, that is actually before the US entered WWII and long before the invention of the cyclotron.

Huh? The cyclotron was invented in 1932. Obviously a relatively primitive instrument (it would easily fit on my kitchen table), but the underlying design is still in use.

Not a collider

[AchilleTalon]

Actually, it is the accelaration module that is 1 foot long. It is not a collider, it is an accelerator a collider would be at least two feet long and in reality would have more than one acceleration module.

SLAC FACET accelerator

[joe_frisch]

I am peripherally involved in the SLAC plasma wakefield accelerator described in the article.

It provides a very high energy gain in a short distance, but needs to be driven by a high energy drive beam. The present design uses a 20GeV drive beam (using part of the old high energy physics accelerator).The required drive beam energy could be reduced to ~10GeV but probably not a whole lot lower. So this is a way to build a relatively short very high energy accelerator, but not a way to build a very short low-medium energy machine.

Other labs are working on laser driven plasma accelerators that do not need to start with a high energy beam, but do need an enormous laser system and are presently limited to much lower average beam powers .

Plasmas are very promising for future accelerators and there was some excellent work done at SLAC as well as laser / plasma accelerators at other labs. There is still a lot to do. There are issues with staging multiple plasma cells to get high energies, beam quality and stability issues etc.

Re:SLAC FACET accelerator

[joe_frisch]

That is a slightly different concept. This uses a medium-energy (20GeV), high current electron beam to drive the plasma, which then accelerates a high energy beam.

There is also a scheme to use a high energy proton beam to drive the plasma, and a scheme to use a high power (Peta-watt) laser to drive the plasma.

All are being seriously considered / developed by various laboratories.

This type of scheme probably doesn't apply well to a circular machine like LHC because the energy limit there is the magnets used to bend the beam into a ring .You might accelerate the protons at the end, but you wouldn't be able to send them back for re-use and you would not get enough collisions to get interesting physics.

Re:so size DOESN'T matter?

[ClickOnThis]

It would have been good form to cite your source.

USA are a country?

[CaptQuark]

The Unites States of America are a country

A group is considered a single entity if all the members of the group are addressed together. You cannot have a group of "United States" be a country without including all 50 of them so they are addressed as a single group. The capitalization of United States of America also indicates you are referring to the collection of all 50 states together.

In contrast, if you said "The Red States are more conservative." then you are referring to the individual states in that group so they are treated as a plural subject.

Other examples: The Pit Crew is efficient, but the pit crew members are tired. The choir is rehearsing, but the choir singers are upset. http://public.wsu.edu/~brians/...

~~

Re:USA are a country?

[Richard_at_work]

It depends on where you come from - its natural here in the UK to use "are" for the collection, eg "Microsoft are..." rather than "Microsoft is..."