New Accelerator Technique Doubles Particle Energy

ZonkerWilliam writes "Plasma wake particle accelerators are making surprisingly quick advances. It was a just a little while ago we had GeV acceleration in 3cm. Now they are capable of doubling the energy of electrons. 'Imagine a car that accelerates from zero to sixty in 250 feet, and then rockets to 120 miles per hour in just one more inch. That's essentially what a collaboration of accelerator physicists has accomplished, using electrons for their race cars and plasma for the afterburners. Because electrons already travel at near light's speed in an accelerator, the physicists actually doubled the energy of the electrons, not their speed.'"

Comments

Cue people who pretend they understand the science

[CRCulver]

in 5, 4, 3, 2, 1...

innerspace

[President_Camacho]

That's essentially what a collaboration of accelerator physicists has accomplished, using electrons for their race cars and plasma for the afterburners.

Those sound like really small physicists.

Only for small values of v

[benhocking]

E=mv^2/2 only for small values of v.

The other formula for E, you might have heard of, is E=mc^2. m = \gamma m_0, where m_0 is the rest mass, \gamma = 1 / sqrt(1 - \beta^2), and beta = v/c. I.e.,
E=m_0 c^2/sqrt(1 - v^2/c^2)
For very small values of v (relative to c), 1/sqrt(1-v^2/c^2) \approx = (1/2)v^2/c^2, which leads back to your formula - but the approximation is only valid for v

Misunderstanding

[erosannin]

I assume you are referencing Dimopoulos and Landsberg's paper http://prola.aps.org/abstract/PRL/v87/i16/e161602 . There is nothing to worry about. These physicists proposed that if certain theories were true (M theory, quantum loop gravity, super symmetry) then the energy densities seen in the RHIC or LHC experiments could produce something "mathematically analogous" to a black hole. There is no possibility under any current theory that an event horizon could form and attract matter.

Don't Knock It!

[StefanJ]

I jammed a butter knife into a 220v circuit when I was a toddler and became a diembodied electromagnetic life-force with super powers.

Other than a morbid fear of lightning rods and antistatic wrist-straps, it pretty much rocks.

I actually work on this at USC!!!

[Brietech]

I actually do some work on this with the PWFA group at USC (i'm an undergrad research assistant). It really is amazing! We can reach acceleration gradients of around 60 GeV/m, compared to something like 40 MeV/m for a normal accelerator. It works like this:
1. The electrons travel down the main linac in carefully spaced "bunches", and get accelerated to around 43 GeV over a course of ~3KM (this is at the main beam at SLAC).
2. A (in the last experiment) 1.2m long Lithium plasma "oven" is at the end of the beam, which the electrons are directed into.
3. The first, or "driving," bunch goes through the plasma, and repels all of the electrons it gets near, leaving an "empty" wake behind it, where only the positively charged ions are.
4. The positive charge behind the driving beam pulls it backwards, causing it to lose energy. At the same time, a "witness" bunch placed strategically within the wakefield gets pulled forward by the positively charged ions. The witness gains energy while the driver loses energy.
5. Voila! One bunch now has twice the energy, and one bunch now has none . . .or at least something close to that!

The main caveat is that you're upward-limited by your entering energy, so you still need a huge Linac to accelerate the bunches to begin with. This will likely get tacked on in the form of a "plasma afterburner" to a normal linac, such as in the setup at SLAC.

Re:We're all going to die!

[General Fault]

Hows the old saying go?
"With the bomb squad, you can usually stop running after the first couple of blocks. If it involves the physics department, keep going."

or perhaps

"We're pleased to announce we are still here to report the results."