Catch up on stories from the past week (and beyond) at the Slashdot story archive

 


Forgot your password?
Close
typodupeerror
×
Science Technology

New Accelerator Technique Doubles Particle Energy 124

Posted by ScuttleMonkey from the double-your-pleasure dept.
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.'"
This discussion has been archived. No new comments can be posted.

New Accelerator Technique Doubles Particle Energy More

New Accelerator Technique Doubles Particle Energy

Comments Filter:

  • OMG FP (Score:1, Funny)

    by Anonymous Coward
    OMG teh fasterzorr elektrons! LOL more FPS!!!!

  • We're all going to die! (Score:4, Funny)

    by BagMan2 ( 112243 ) on Wednesday February 14, 2007 @06:07PM (#18017126)
    One of these days those crazy scientists are going to do something and we will all just disappear into a mass of energy.
    • There's talk about creating mini black holes with the upcoming particle accelerator coming online in a few years (I don't remember what it's called). But apparently, these mini black holes will evaporate very quickly, so there's no danger in creating a black hole that will go out of control. I hope they're right.

      • Misunderstanding (Score:5, Informative)

        by erosannin ( 898004 ) on Wednesday February 14, 2007 @06:27PM (#18017330)
        I assume you are referencing Dimopoulos and Landsberg's paper http://prola.aps.org/abstract/PRL/v87/i16/e161602 [aps.org] . 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.

      • Old Chestnut (Score:3, Informative)

        by Morosoph ( 693565 )
        Black holes "suck" only as much as the mass that they contain does.

        Any black hole created in a lab on earth is going to have negligable sucking power, since the mass in them will be tiny. The vision of a black hole forming and swallowing the earth is great sci-fi, but (happily) poor science. At worst, it will hang around, swallowing the odd electron at very rare intervals.

        • Any black hole created in a lab on earth is going to have negligable sucking power, since the mass in them will be tiny.

          Hmmm ... not being a physicist I don't want to strongly refute this, but I'm kinda curious.

          Yes, any black hole created by us would initially have negligible mass. But, since it's not created in a vacuum, wouldn't it start accumulating mass fairly quickly? I should think it would start pulling in bits from the atmosphere.

          I have no idea about the energies and life cycles of really small bl

          • Yes, any black hole created by us would initially have negligible mass. But, since it's not created in a vacuum, wouldn't it start accumulating mass fairly quickly? I should think it would start pulling in bits from the atmosphere.

            Practically speaking, it would evaporate through Hawking Radiation in no time, however, whenever this comes up, someone points out that we're playing God, and don't really know what will happen (probably fresh from watching some disaster movie).

            So assuming that this Hawking

            • So assuming that this Hawking Radition (that we actually observe) doesn't exist, you have a point concentration of mass (a black hole) with (say) the mass of a grain of salt. Not only is the pulling power of a grain of salt pretty small, but a particle that is attracted to it has to actually hit the miniscule event horizon. This won't happen very often.

              Hmmm ... I guess. I was thinking that in order to be a black hole, it would have to start out with a larger mass than a grain of salt. I had (probably mist

    • Don't Knock It! (Score:5, Funny)

      by StefanJ ( 88986 ) on Wednesday February 14, 2007 @06:28PM (#18017342) Homepage Journal
      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.

    • Re:We're all going to die! (Score:5, Funny)

      by General Fault ( 689426 ) on Wednesday February 14, 2007 @07:57PM (#18018212)
      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."

    • Re: (Score:3, Funny)

      by DamnStupidElf ( 649844 )
      One of these days those crazy scientists are going to do something and we will all just disappear into a mass of energy.

      Don't worry, there's always an alternate universe where the experiment fails.
    • The hadron super -collider in Switzerland is proposed to produce a blackhole albeit a scant millimeter or so in five years. Hold on to your collective you know whats.

      • Re: (Score:2, Informative)

        by zuiraM ( 1027890 )
        Even if you generate these at an enormous rate, you'll still end up gobbling up a few protons a year. Heat death of the universe will be an issue before those micro black holes are. Remember that black holes' anomalous effects at close range are due to the *density* of the matter, while the long-range effects are based on their total mass. As for the former, "close range" for a micro black hole is such that one would most likely pass through the earth without a single particle coming within range on the way
    • Why do you think there aren't any aliens? At some point, every sufficiently advanced society makes the same stupid mistake and disappears into a blast of gluons, quarks, and gamma radiation. It's God's way of weeding out the wise from the smart.

  • Comment removed (Score:5, Funny)

    by account_deleted ( 4530225 ) on Wednesday February 14, 2007 @06:09PM (#18017138)
    Comment removed based on user account deletion

    • Re:Cue people who pretend they understand the scie (Score:3, Interesting)

      by Anonymous Coward
      You might not believe it but there are some bona-fida scientists skulking about slashdot.
    • Forget portable cancer treatments, I want to bust some ghosts. Or at least get paid to blow the crap out of a fancy hotel. Never mind the part about it still needing two miles of pre-acceleration before the plasma wakefield thingamabobby kicks in, that's just a minor hiccup. Proton packs [wikipedia.org] are just around the corner.

      Ahhhh, I love the smell of burning ectoplasm in the morning! It smells like victory.

    • Re:Cue people who pretend they understand the scie (Score:2, Funny)

      by Anonymous Coward
      Cue the crackpots who deny the science.

    • Re:Cue people who pretend they understand the scie (Score:5, Insightful)

      by Mr. Underbridge ( 666784 ) on Wednesday February 14, 2007 @09:28PM (#18019122)

      Cue people who pretend they understand the science...

      As mentioned, there are some of us around here who are actual scientists. However, there are no details in the article, thus no science to understand. All I found were crappy analogies with afterburners and some hand-wavey crap about plasma. I'm pretty sure that if it were as easy as running some crap through a plasma to accelerate it, it would have been done some time ago. And there are a number of pertinent questions:

      Why do they have to use a 2-mile accelerator if the plasma can do in a foot what it takes the 2 miles to do?

      Why can't it be longer?

      How is the plasma chamber set up? I'm guessing it's probably an coupled with an RF field, which can accelerate a plasma, but details, come on!

      • Based on the document the device probaply works in a way that an electromagnetic wave beats up the spead. Acoording to the article and some pubolcations of the LHC not all the input catches it's flight on those waves. This results in spreading of those particles, spreading in spead/energy/beam overall its not delieverd as how those particles run trough exactly timed intervals in a focussed way as in the currently operative LHC. The spreading gives the output a randomnes which i gues, a lot of scientist wou

  • E=1/2 m v^2 (Score:5, Informative)

    by leehwtsohg ( 618675 ) on Wednesday February 14, 2007 @06:11PM (#18017162)
    The kinetic energy is proportional to speed^2 (E=1/2 m v^2), so a car at 120mph has 4 times the energy of a car at 60mph. Thus, doubling in energy is not like doubling in speed.

    • Re:E=1/2 m v^2 (Score:5, Insightful)

      by qbwiz ( 87077 ) * <john@baumanfamily.c3.1415926om minus pi> on Wednesday February 14, 2007 @06:24PM (#18017294) Homepage
      Well, you're right when you don't account for relativity. When you're going at .99c and you double your energy, you don't start going at 1.4c.

      • Re:E=1/2 m v^2 (Score:5, Funny)

        by UbuntuDupe ( 970646 ) * on Wednesday February 14, 2007 @06:45PM (#18017520) Journal
        I didn't know 60 mph was close to c. Maybe for large values of 60? ;-)
        • I didn't know 60 mph was close to c. Maybe for large values of 60?

          Or relativistic hours? I mean 'miles per hour' for a person travelling at relativistic speeds would be different from 'miles per hour' for a non-relativistic observer wouldn't it, since time dilation would mess with the hours? Or something like that?

          • Re: (Score:2)

            by dkf ( 304284 )
            No, miles-per-hour are exactly the same for an observer moving at relativistic speeds as for a stationary observer. This is not intuitive, but it is true nonetheless. It's just that the stationary observer's miles-per-hour are not the same as the relativistic observer's, which you can regard as being the results of Lorentz contraction on the spatial dimension parallel to the direction of travel and corresponding time dilation so that things still do not look different to those on the inside.

            (I think I got t
      • Speed isn't the important thing in a particle accelerator. They're not racing the electrons, they're smashing particles.
    • In this domain though, doubling the energy corresponds to a very small increase in speed. E = p^2/2*m is just the first order term in an expansion of E = Sqrt[m^2*c^4 + p^2*c^2], and p = m*v*(1 - v^2/c^2)^(-1/2). Thus doubling the energy corresponds to a speed difference of 0.0166415572 m/s. That's 5.5e-9 % increase in speed. One way to think of if (although technically it's not correct), the mass of the electron at 42GeV is 82,000 times it's rest mass, and the velocity increase needed to increase its energ
      • I always thought that doubling your energy at near relativistic speeds puts you halfway between the speed you were going and lightspeed. Which of course means you will never get there you just keep getting half way there. Oh well I've been wrong before :)
  • Unfortunately, these concepts will not be applied to the next generation of high energy accelerators. The International Linear Collider will supplant the Large Hadron Collider some time after 2015, but relies on superconducting static-gap technology and will be 30-40 kilometers long. Perhaps the next generation of experiemnts will employ plasma accelerators?

    • Re: (Score:1, Informative)

      by Anonymous Coward
      The International Linear Collider will supplant the Large Hadron Collider some time after 2015

      The ILC will not "supplant" the LHC, they are completely different machines, accelerating different kinds of particles, making the suitable for different kinds of studies.
    • Yes, it'd be great if we could accelerate particles like this for the "next next big thing" after the ILC. Unfortunately, the energy levels using these and other exotic techniques are not yet all that high.

      Notice that the electrons are spun at SLAC for about 2 miles up to 43 GeV, then this technique about doubles the energy to 85 GeV in 33 inches.

      However, they still need to show that this can be done again and again; the ILC will be in the range of 500-1000 GeV. I only work with particle physicists (mathe

    • Luminosity (Score:5, Informative)

      by jpflip ( 670957 ) on Wednesday February 14, 2007 @07:14PM (#18017836)
      As I understand it, luminosity is one major reason why this technology is not yet ready for prime time (i.e. not in time for the proposed ILC). You can't just accelerate a few particles to high energies and say you are done. You're looking for rare processes, so you need to create many consistent particle collisions per second in a tiny area. This means you need to have a tight, "bright" beam. The Tevatron has a luminosity of ~2e+32 interactions/cm^2/s now, the LHC may eventually reach 1e+34, and the goal for the ILC is more like 2e+34. Plasma wakefield systems are now demonstrating large increases in energy over short distances, but it's very difficult to daisy-chain them together to reach high total energies with any significant luminosity.
      • You can't just accelerate a few particles to high energies and say you are done. You're looking for rare processes

        Unless you are just looking to punch great smoking holes in tanks or something?

        • Re: (Score:3, Funny)

          by QuickFox ( 311231 )

          Unless you are just looking to punch great smoking holes in tanks or something?
          This should work fine, as long as you don't mind having to carefully sneak up to within millimeters from the enemy tank while lugging a two-mile accelerator.

  • innerspace (Score:5, Funny)

    by President_Camacho ( 1063384 ) on Wednesday February 14, 2007 @06:17PM (#18017218) Homepage
    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.

    • Re:innerspace (Score:5, Funny)

      by Dachannien ( 617929 ) on Wednesday February 14, 2007 @06:26PM (#18017302)
      using electrons for their race cars and plasma for the afterburners

      And their wives still say they're compensating.

      • Re: (Score:2, Funny)

        by boarsai ( 698361 )

        And their wives still say they're compensating.

        So what you're really saying is we should have done physics instead of IT, as they have the women. Bastards.

        • Yep they've got full benefits packages.... and tenure, so they can't get downsized ;-p nothing a woman loves more than a full package.
    • Those sound like really small physicists

      At least we know what happened to the Indonesian Hobbits. They didn't die out the evloved into physicists.

  • From the article description: '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.

    Say hellow to jello bones.

  • Re: (Score:2, Offtopic)

    by account_deleted ( 4530225 )
    Comment removed based on user account deletion
    • Bah! In my day, and in my state, we just bore through rocks! And we WERE grateful!

      Unfortunately, the SSC 54 mile ring would have accelerated protons to 20 TeV and was never completed. I can only imagine with this plasma infusion what might have been and never was. If only...
  • 1/2 mv^2 is the non-relativistic kinetic energy. The mass correction will change the energy rapidly as v approaches c. The mass correction [wikipedia.org] with the Lorentz factor [wikipedia.org]in that expression are needed to get the correct relativistic energy.
    The lorentz factor is 1/sqrt(1-(v/c)^2); at 0.99c it will multiply the mass (and energy) by a factor of 7; at 0.999c it will multiply everything by a factor of 22.3.

  • For the Americans here (Score:5, Funny)

    by lelitsch ( 31136 ) on Wednesday February 14, 2007 @06:32PM (#18017386)
    They increased the mass of the electrons by 1.65064935 × 10-27 hundredweight in 0.00032808399 football fields. Sorry, I don't know how much that is in SUVs.

    Seriously, though, this is a neat trick. (Yes, IAAP)

  • The example is stupid... (Score:3, Insightful)

    by sealawyer2003 ( 688442 ) on Wednesday February 14, 2007 @06:54PM (#18017626)
    '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. First of all at non relativisitc speeds, doubling the speed results in a four fold increase in kinetic energy and not a doubling. Why give a bad classical mechanics analogy and then tell us that the speed didn't actually double because of relativistic effects.
    • Imagine a bunch of cars that accelerate from zero to sixty in 250 feet, then slam into a barrier, causing a multi-car pileup from which, starting just one inch further down the road, one of them rockets out at 85 miles per hour.

      (Obviously they were inspired by the traffic on Interstate 280 on their way to SLAC. B-) )

  • I actually work on this at USC!!! (Score:5, Informative)

    by Brietech ( 668850 ) on Wednesday February 14, 2007 @07:01PM (#18017692)
    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.
    • I've not read any of the technical papers on this yet but off hand I wonder if a) you can ever get the same luminosity as more traditional methods and b) how well can this be used for heavier particles?   I suppose the first real world use
      would be as an injector?

      • Re:I actually work on this at USC!!! (Score:4, Informative)

        by Brietech ( 668850 ) on Wednesday February 14, 2007 @07:27PM (#18017976)
        As far as I understand it, it doesn't work nearly as well for heavier particles (I assume you are thinking protons?). Especially ones with a positive charge. The heavy mass of the protons compared to the electrons in the plasma cloud are what allows the "wakefield" to be created in the first place. When we model this stuff, the ions move so slowly compared to the electrons that we generally just assume that they are static for the duration of the beam passing through the oven (pico-femto second range). As I mentioned earlier, this will most likely always show up as an "afterburner" that goes at the end of a traditional linac.

        • Re: (Score:2)

          by sanman2 ( 928866 )
          Can you maybe use this thing for accelerating other exotic particles, like muons? I'd read that muon colliders are being researched because they as point particles might arrange for cleaner point-collisions with enough kinetic energy to serve as "Higgs factories". A "Higgs factory" device which could produce lots of Higgs particles might then make it much easier to find/study the "God particle". (Even exploit it?)

          Because laser wakefield / plasma wakefield accelerates things so quickly and so suddenly, perha
        • You still have one issue with this form of wake field acceleration, Luminosity! The luminosity goes way down, ~1% of what the original electron "bunch" was.

    • 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.
      sounds like a slingshot pass in NASCAR. Shake-n-Bake, baby
    • Understandably, one wants the bunches to be small. Wouldn't this mechanism tear the bunches apart, and give them much higher temperature (i.e. spread out energy distribution)?

      • Re:I actually work on this at USC!!! (Score:5, Informative)

        by Galahad2 ( 517736 ) on Wednesday February 14, 2007 @10:23PM (#18019518) Homepage
        I attended a talk from one of the primary investigators on this project a few months back. The system does indeed spread out the distribution, which can be bad for some circumstances. When all you care about is the peak energy, however, it's great. They call it a plasma afterburner.

        One thing that isn't obvious is that you can't use two of these devices to double the energy twice. One doubling is all you got. Apparently there's some theorem in plasma physics that a Gaussian distributed pulse (as SLAC is) can only be energy-doubled by any method or methods once. I don't know the details of this, and I might be misrepresenting it, but there you go.

        By the way, I think you have a misconception about temperature. It's true that a higher temperature gas has a wider energy spectrum, but the primary piece of information you're interested in is the average velocity. The statistical distribution is a function of only one variable -- you can't "spread out" the distribution to increase the temperature without simply dumping energy into the system. If you somehow separated the particles into low average energy and high average energy, you'd just have two classes of particles with two temperatures, not one cumulatively higher one.
    • Is it likely that these accelerators can be cascaded to get higher energies?
    • Comment removed based on user account deletion
      • my laymans understanding is: particle accelerators are used to study the basic building blocks of our universe, and as they get more powerful (ie they can give the accelerated particles higher energies ) they see new levels of building blocks EG:

        imagine the world is made of Lego shaped into the form of duplo. Before we had particle accelerators, we might have thought we were made of duplo. By smashing the "faux duplo" together, we realize there's Lego in there(*). if we throw it even harder at each other,

  • "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.... Because electrons already travel at near light's speed in an accelerator, the physicists actually doubled the energy of the electrons, not their speed."

    Hmm. Well which is it, are we doubling velocity or engery? I'm no rocket surgeon, but I'm pretty sure these are different things. If it's energy then I think the analogy should have been, "...and then rockets to 85 miles per h

    • Re: (Score:2)

      by 1u3hr ( 530656 )
      Imagine a car...

      You KNOW when someone use a car analogy to "explain" a highly technical or abstract concept that it will make no sense. And worse, will start up a whole bunch of threads about cars, driving, etc, etc.

  • Is this going to improve my 3d graphics accelerators?
    • Is this going to improve my 3d graphics accelerators?

      No, but watching you being bombarded by relativistic subatomic particles would be much funnier than reading your comments.
  • All your electron-Volts are belong to us.

    Only Old North Koreans need souped up particle accelerators.

    In Soviet Russia, particles accelerate YOU!

    What did I forget?

    • Re: (Score:2)

      by alc6379 ( 832389 )
      Step 1: Double Particle energy.
      Step 2: ???
      Step 3: PROFIT!!!

      Not really a Slashdotism, but it is WAY over used here...

  • If the collimated beam going into the plasma chamber gained a bunch of energy (42GeV) in the space of 84cm, that means total time of flight in the chamber was in the nanosecond range. That means a jillion collisions with the plasma. Wouldn't this screw up the focus of the beam? Sure, you've got a more powerful pulse of electrons coming out, but they will be sprayed all over the place, so the amount of energy that you can put into your incoming target beam of positrons (or into a stationary target) is dilute

Slashdot Top Deals

Beware of Programmers who carry screwdrivers. -- Leonard Brandwein

Close