World's Largest Supercooled Magnet Activated

An anonymous reader writes to mention a C|Net article about the activation of the world's largest superconducting electromagnet. Switched on today at Geneva's CERN lab, the experiment is part of the Large Hadron Collider (LHC) project. The magnet, called ATLAS, worked on its first start up. From the article: "In use, the magnet will be used to bend the paths of particles formed from the collision of protons or lead ions accelerated to near light speeds in 27km diameter subterranean contra-rotating circular beams. The ATLAS experiment is one of five in the LHC, and engages 1,800 scientists from 165 universities and laboratories in 35 countries."

Comments

Might be painful

[Anonymous Coward]

Hope no one with ferrous implants is around that thing~

Re:Might be painful

[odourpreventer]

It's a moot point, since the radiation would kill you. But yes, in the sections where people are allowed, the electro-magnetism does some funky stuff to TV-screens (but those are different electro-magnets). That was the case in -99 at least.

Worlds largest bulk magnetic media eraser...

[binaryspiral]

And every single magnetic based media for ten miles was instantly erased.

A faint "bwa ha ha ha... vhs tapes and floppy disks suck!" was heard from from the evil scientists' lair.

Re:Worlds largest bulk magnetic media eraser...

[Fred_A]

No wonder I had to degauss this morning...

Re:Worlds largest bulk magnetic media eraser...

[Anonymous Coward]

Hey, don't scare me like that. I live well within 10 miles of that thing!

Re:Worlds largest bulk magnetic media eraser...

[Anonymous Coward]

Well, there go my backups. By the way, I do work in Geneva.

Re:Worlds largest bulk magnetic media eraser...

[OakDragon]

Now I know where to look for my car keys...

It's taking a long time

[BadAnalogyGuy]

The original team working on this tried to load the software from floppies.

Re:It's taking a long time

[RuBLed]

Now that it is functional, I doubt that those floppies would work now. I hope they made backups.

Re:It's taking a long time

[Anonymous Coward]

Wooosh

Re:It's taking a long time

[pakar]

Yea, they kept the backups on the opposite side of the complex. =)

eek!

[hotcakes.co.nz]

eek! what next, they'll be bending light next with magnets???

why

[tezbobobo]

I know the article says what it will be used for, but why do we need to bend the particles path, and why does the magnet need to be super cooled?

Re:why

[Peden]

All in the name of research baby. "The internet" as we know it was in part created at CERN, if that does not merit researching high energy particles, I don't know what does. http://www.hitmill.com/internet/web_history.html

Re:why

[hcdejong]

IANAPP (particle physicist), but bending the particles' path is often done to determine mass: heavier particles will be pulled off their course less than lighter particles, so they'll impact the detector in a different place.

The magnet needs supercooling because a huge magnetic field is easier to achieve with a superconductor than with a conventional magnet.

Re:why

[Nanpa]

Well, I'm not exactly sure why you would want to bend the path around, but the electromagnet is made from a superconductor. A superconductor will allow massive currents to be carried with no electrical resistance, but unfortunatly must be kept under a specific temperature to retain its superconducting properties. Because the superconductor can carry massive amounts of current with little resistance, a strong magnetic field can be created (As the strength of the electromagnet is dependant on the current being used.). Have a look at the wiki article http://en.wikipedia.org/wiki/Superconductor

Re:why

[Gromius]

We need to bend the particles path so we can measure its momentum. A charged particle in an magnetic field will have a radius of curvature inversely proportional to the magnetic field and proportional to its momentum, with opposite charged particles curving in different ways. The radius of curvature decreases as the magnetic field increases and increases as the momentum of the particle increases. So for very high momentum particles, the radius of curvature is very large so the particle travels in almost a straight line which makes it very difficult to measure the radius of curvature. Hence you increase the magnetic field to force the particle to "bend" more and make it easier to measure the amount of "bending". So you want as big as magnetic field as possible and at the moment superconducting magnets give the most powerfull fields.

Here, have a look at this picture of a particle physics event (not from ATLAS but CDF at the Tevatron but the idea is the same). Lines in the circle are particle tracks, the two pink ones are very high momentum charged particles (in this case electrons). Notice how they are straight. As such we dont have a very good measurement of their momentum. The other grey lines are low momentum particles as they bend a lot since the radius of curvature is small.

Why do we want to measure the momentum of a particle? Well the Higgs boson (if it exists) will decay to 4 muons (basically heavy electrons) (nb: the Higgs can decay to other stuff but for a heavy higgs this is the cleanest signature and will be how its discovered). You want to measure the momentum of these muons and from that you can measure the mass of the particle that produced them. If you get a lot of events at a certain mass above what you expect from background, you've just discovered a new particle, likely to be the Higgs.

Re:why

[romain wartel]

> why do we need to bend the particles path

I am not a particule physicist, but the particules need be accelerated and are 'pushed' by the magnets before being collided, so they need to circulate many times around the accelerator in order to get sufficient speed.

"A beam might circulate for 10 hours, travelling more that 10 billion kilometres, enough to get to the planet Neptune and back again. At near light-speed, a proton in the LHC will make 11 245 circuits every second."

What is the LHC power consumption?

It is around 120 MW which corresponds more or less to the power consumption for households in the Canton (State) of Geneva."
http://public.web.cern.ch/Public/Content/Chapters/ AskAnExpert/LHC-en.html

> why does the magnet need to be super cooled?

To magnets are used also to maintain the beam within its path, and the requires huge amount of energy to create a magnetic field that is strong enough to prevent the beam to escape. These magnets are using a massive amount of power, and must be cooled down (a lot) do reduce their electrical resistance down to supraconductivity.

"In order to cool the magnets down to -193.16 C (pre-cooling), 10 080 tonnes of liquid nitrogen will be used. Afterwards, the refrigerators turbines will bring the helium temperature down to -268.7 C and fill the magnets with almost 60 tonnes of liquid helium. Once the magnets are filled, the refrigeration units will bring the temperature down to -271.3 C by lowering the saturation pressure - and therefore the temperature - of the liquid helium in a heat exchanger in contact with the static pressurized helium of the magnets' cold masses."
http://public.web.cern.ch/Public/Content/Chapters/ AskAnExpert/LHC-en.html

http://en.wikipedia.org/wiki/Large_Hadron_Collider
For reference, the LHC will also use a massive computing Grid: http://www.cern.ch/LCG/

Romain.

Re:why

[Anonymous Coward]

Because the accelerator is circular. In a linear accelerator you only get one trip to acclerate the particles and one shot at the collision. In a circular path the particles can be accelerated on each trip around and can have multiple collision points. Plus if you're colliding particles and anti-particles, the same magnets can be used. The advantages of higher energies, counter-rotating beams and multiple collision points are somewhat offset by the need to have bending magnets and the loss of energy through synchrotron radiation.

Superconducting electromagnets retain their magnetic field effectively indefinitely - the current that generates the field will circulate forever because there's no resistance.

Re:why

[hcdejong]

You seem to suggest the ATLAS magnet is used to contain the particles within the accelerator itself, which is not the case.

The accelerator does use magnets to contain the particles, just not this one.

The ATLAS experiment is one of the detectors which use the output from the accelerator.

Re:why

[bmgoau]

Actually No, particle accelerators such as this are called cyclotrons and their ring shape is such that any particle placed within them can orbit a central point until the deisered velocity can be reached by proceeding through the same series of magnets over and over again, often close the speed of light. This is opposed to a cheaper and simpler liniar accelerator, which shoots particles down a long and stright tunnel.

This is because we already know the mass of the particles (such as molecular and atomic ions and hardrons) being used in the accelerator, and other means are used to dertermine the mass of the particles resulting from the collisions such measirng the radius of curves made in bubble-chambers close to a collison point.

This is also why it is called a Hadron Super Collider.

Re:why

[Gromius]

No, not in this case (good try but you're thinking clasically). This may be true at low speeds but the particles detected in these experiments that are of interest are relativistic and are moving at signficant fractions of the speed of light (about 0.999c or there abouts) and as such for all intents and purposes have zero mass. These particles are often the decay products of more massive particles. The reason we want to bend them is to measure their momentum (or spectifically their transverse momentum) NOT their mass. We can then add together the momentum of these particles to obtain the momentum of the orginal particle from which we can get its mass using special relativity.

Just your friendly neighbourhood particle physicist.

Re:why

[romain wartel]

Basically, the accelerator itself and therefore the particules are going through ATLAS. Collisions between particules (going in opposite directions) are setup to happen within the core of ATLAS. The objective is to build various layers of (different types of) detectors around this point of collision to search for specific particules with a very short lifetime generated by the collision.

http://atlas.web.cern.ch/Atlas/TCOORD/Activities/I nstallation/atlas_overview.gif

These differents layers of detection generate lots of data that is filtered to isolate a few 'interesting' events, which can then be processed by the computing Grid.

Romain.

Re:why

[hcdejong]

Actually, no. The LHA is not a cyclotron. In a cyclotron, the particles travel in a spiral, in an area sandwiched between two huge electromagnets. The size of the magnet limits the size of the cyclotron.
The LHA consists of a tube running through a series of magnets, a bit like a linear accelerator. The tube is bent into a circle so you can have the particles do multiple laps around the accelerator to increase their energy.

Re:why

[benplaut]

It's an end to global warming, of course!

Re:why

[Lord Crc]

I know the article says what it will be used for, but why do we need to bend the particles path

As found on this page, the magnet is used to measure the momentum of the particles. I'm not into physics, but I imagine it's a bit like rolling (equally sized) balls along a line, and then have a fan on the side trying to deflect the movement. A large momentum (and thus mass, assuming all the balls travel at the same speed) would lead to less deflection.

Re:why

[WhatAmIDoingHere]

"Want a Catholic discussion board? Help me start it."

There is no such thing as an invisible man. Wake up and stop believing a fairy tale.

Re:why

[bockelboy]

A Higgs -> 4mu is probably how it would be discovered *if* it exists, of course. Plus, you have your more exotic decays; I bet they'll want to see a couple of those before they confirm the existence of the boson.

Of course, the article fails to mention that CMS has been doing the magnet test / cosmic challenge for a couple of months now.

Besides, it won't be discovered by ATLAS, but by CMS! (Guess which collaboration I'm with...)

Re:why

[Anonymous Coward]

ATLAS??

No wonder ...

Re:why

[Anonymous Coward]

This gets modded informative??

You are completely missing the point. This magnet is not part of the accelerator, it is part of a *detector*. And inside it, the radius of the curve a particle describes (together with timing data) is used to determine its mass.

Superconductivity is needed to be able to achieve the huge currents used to build up the magnetic field in limited space - and to keep energy losses (and heating!) due to resistance inside the detector as low as possible. The energy stored in the magnetic field is enormous, a breakdown of superconductivity (which hopefully will never happen) would melt "fuses" consisting of massive copper blocks.

And yes, IAAPP at CERN, working on the CMS, another detecor there.

Re:why

[hcdejong]

Did you read my post and its parents? I am perfectly aware that the ATLAS isn't part of the accelerator (and have said so in other posts to this story). I was merely answering a post that erroneously describes the LHA as a cyclotron.

Re:why

[Iron Condor]

"The internet" as we know it was in part created at CERN,[...]

Well, they sure know their way around tubes...

Re:why

[arminw]

Another difference between circular accelerators is that the circular type cannot accelerate electrons to very high energies, because electrons radiate much more energy at any given bending radius. At some point there is simply no way to impart more energy to them than they radiate away. That is why electrons are accelerated in linear accelerators, such as the two mile one at Stanford. Circular machines use protons and their anti counterpart. Because electrons are simpler than protons, their collisions produce easier to interpret data.

Here they come...

[Anonymous Coward]

...thousands more of the "Large Hadron" jokes. I suspect there are already plenty by the time i hit "submit".

Impressive stuff

[Hyksos]

I've seen the magnet while it was still being constructed. Suffice to say, BIG is an understatement! :)

Re:Impressive stuff

[trip11]

Bah, the muon detector 'big wheel' is way more impressive (: Ok, not that the magnets aren't cool too.

Re:Impressive stuff

[l0b0]

How's this for size? ATLAS calorimeter, the tunnel, one of the tubes, the "crab", the hole, and the cavern. Bonus: They do have retina scanners!

Re:Impressive stuff

[10Ghz]

And now that it's finished, I bet it's quite attractive as well!

Re:Impressive stuff

[Anonymous Coward]

> cool

At -269C, you bet!

Re:Impressive stuff

[Bob of Dole]

crabs and retina scanners? I think I've played this game!

"They're waiting for you Gordon... in the test chamber"

(What is it with people in that series and emphasizing random words? "Wake UP! Wake up and smell the ASHESEHESSS....")

Re:Impressive stuff

[randomblast]

Calorie meters? You mean I don't have to count them myself anymore?

The realy deep questions

[Silver Sloth]

From TFA

the LHC will be the most powerful particle accelerator ever built and will be used to investigate why particles have mass

It's at this point I realise how amazingly little I know about particle physics. In my ignorance I always thought that having mass was an inherant property of being.

Re:The realy deep questions

[tkittel]

It might have been an inherrent property of all particles (except the massless photon and gluon), but it turns out that the nature of the weak force (normally known from beta decays of nuclei) conflicts with this.

The real understanding of this problem requires knowledge of Quantum Field Theory, but the gist of the problem is as follows:

All known matter particles (fermions) as well as the particles that mediates the weak force (the W and Z) behaves in experiments as if they have masses. However, if they actually do have masses the theory breaks down (it becomes non-renormalizable, and gives non-sensical answers such as "that decay have a branching ratio of 500%". It becomes a bit like sports-commentators, I guess).

The proposed solution to this conundrum, and the one the LHC and ATLAS will try to verify, sounds kind of like a lawyer finding a legal loophole when you first hear it. In essence it is: "All particles are really massless, but some of them behaves as if they have mass". The way to accomplish this is by the so-called Higgs Mechanism, in which particles acquire masses the same way that a light-weight guy walking in a waist-high pool will feel as much or more difficulty walking as a really fat guy walking on dry ground: All particles move around in a soup of Higgs particles and thus acquire the appearance of being massive due to their interactions with this Higgs-soup.

I thought it was kind of cheesy back when I first heard about it, but later I realised that similar effects already are known to happen elsewhere in nature, which kind of makes it more acceptible (for instance, those familiar with the Meissner effect for superconductors might recall how the otherwise massless photon acquires the appearance of mass inside superconductors due to the presence of a soup of electronic cooper-pairs).

But we will have to see when the LHC starts!

ps. I am actually a member of the ATLAS collaboration. Go magnets!

Re:The realy deep questions

[vikingpower]

Hmm. Mass may not be an inherent property of being, but inertia must be, no ?

Re:The realy deep questions

[Silver Sloth]

Many thanks for a coherent and understandable (for particle physics!) response. As ever I'm left going 'Wow' Have fun with your magnets.

Re:The realy deep questions

[myowntrueself]

All particles move around in a soup of Higgs particles and thus acquire the appearance of being massive due to their interactions with this Higgs-soup.

Oh so the Higgs-soup is kind of like phlogiston or something similar?

Re:The realy deep questions

[Mr2cents]

All particles move around in a soup of Higgs particles and thus acquire the appearance of being massive due to their interactions with this Higgs-soup.

How would that be possible? I thought that this Higgs particle was highly unstable and decays almost immediately. So where does the soup come from?

NB: I'm no expert.

Re:The realy deep questions

[Anonymous Coward]

Wouldn't it make sense to describe particles as massless, and attribute their mass-like qualities to the (possibly inertial) movement of the individual components that make up the particle? Kind of like when my gyroscope feels heavy because it's moving fast, but traveling in a fixed orbit.

Re:The realy deep questions

[Anonymous Coward]

Not exactly.

More like quantumiferous aether.

Re:The realy deep questions

[FiloEleven]

This proposed solution, to my layman's eyes, reeks of ether.
-f

Re:The realy deep questions

[dargaud]

I always thought that having mass was an inherant property of being.

And I thought that only catholic beings had mass... must have been mistaken.

Re:The realy deep questions

[Have Brain Will Rent]

Think of inertia as one word name for the law of conservation of momentum. For the momentum of something to change it must be acted upon by something else... if it isn't then its momentum will not change, which is what is usually said to describe inertia. These are all somewhat fluid concepts... going through school first you learn that photons have no mass... but later on you will learn that photons have momentum ... and of course momentum is usually defined as Mass x Velocity...

Energy Consumption

[chriss]

From TFA:

The LHC will consume some 120 megawatts and is predicted to run for between 15 years and 20 years. It will be rested for three months in winter because the French power station that supplies it is needed for the domestic grid.

So I guess almost all the world's particle physicists will be home for christmas.

This is just a part of Large Hadron Collider

[RuBLed]

This was once featured on slashdot and for those confused, this is just a part of the world largest (longest) particle accelerator thing and one of the purposes of this huge facility is to generate small blackholes.

http://public.web.cern.ch/Public/Content/Chapters/ Spotlight/SpotlightATLAS-en.html

Re:This is just a part of Large Hadron Collider

[trip11]

IAAPP. Just so no one freaks out over this (as they so often do). The black holes that are getting created here will not destroy the earth. First off the theory tells us that black holes with less than, say the mass of the earth, will dissapate and dissapear (this is one of the things we are looking for). So for those of you thinking, what if they are wrong, I present the second argument. The experiment we are trying to set up at ATLAS and the Large Hadron Collider to smash really high energy particles together is done in nature every day. Cosmic rays smash into the earth's upper atmosphere with WAY more energy than we can every hope to achive here in Switzerland. If we can make black holes here, then many have been made in the upper atmosphere. The problem is that they are hard to observe way up there, occurring at random chance. However the fact that the earth is still here is damn good evidence that the back holes don't grow and destroy the earth when they are created.

Re:This is just a part of Large Hadron Collider

[bmgoau]

Actually, the Large Hadron Super Collider does not have the creation of micro-singularities (aka black holes) in its objectives. Infact, some politions were concerned about this possibility, and scientists involved in the project to build the LHC did reseach into the possibility. They concluded that this accelerator does not have the power needed to collide particles at velocities needed to create small blackholes. Several orders of magnitude more power is requiredto do this.

The LHC is designed to verify many particle physics theories such as the possible existance of a Higgs Boson, or even a Meson responsible for the existance of mass, and at the greatest length, even may confirm the existance of a graviton.

Infact, even if two subatomic particles were able to be forced into a black hole, the result would be null since they would instantly decay due to hawking radiation.

Re:This is just a part of Large Hadron Collider

[Anonymous Coward]

Shush! Experiments sound so much more impressive if people think there's at least a small chance they might destroy the Earth.

I mean, which is more impressive:

"Hi, I'm a particle physicist. We have a really big electromagnet. It's part of the Large Hadron Collider project."

or:

"Hi, I'm a particle physicist. We have a really big electromagnet. It's part of the Large Hadron Collider project which MIGHT DESTROY THE VERY EARTH ITSELF! Mua ha ha ha!"

Re:This is just a part of Large Hadron Collider

[atria]

IAAPP and that part with black holes is pure fiction. A black hole is a singularity at level of space-time fabric. Quark Pluon Plasma is a state in which quarks and gluons are almost free because of high confined state. From what we know until _now_ one has nothing to do with the other.However, __IF__ they(black holes) will be produced, the evaporation time will be at level of ns. So .. the afirmation that: "one of the purposes of this huge facility is to generate small blackholes" is completly false. Better read at www.cern.ch and also http://aliceinfo.cern.ch/ (home page of ALICE experiment) which is an experiment dedicated to study of Quark Gluon Plasma

Re:This is just a part of Large Hadron Collider

[MindKata]

In the interests of scientific debate, (of which critical evaluation is a vital part), I'm going to play devils advocate for a moment...

The mini Black holes issue. On the one side we have people who say black holes are not possible and on the other side, we have people who say black holes are (maybe) possible.

Right so we have theories such as for example...
(1) Higher energy collisions occur in the atmosphere.
(2) The LHC does not have the power required.
(3) Some people also bring in the concept of Hawking radiation.

With point (1) we actually have an assumption which is a fair assumption, however the conditions within the LHC are different to that of the atmosphere. For example we have a concentrated particle beam than would not occur naturally in our atmosphere (or coinciding with such high magnetic fields in our atmosphere) etc... So while we can assume these are unimportant we cannot be certain and we are going to be getting the potential for a lot of high energy collisions spraying around within the machine.

With points (2) and (3) we have theories and theories based on other theories all of which look correct. However, the LHC is being built for a number of reasons and one of the central reasons is we want to extend our knowledge to prove if our theories are 100% correct. We can also say with 100% certainty that our current theories are incomplete as they do not work in all circumstances. Hence one of the main reasons to continue to do experiments such as building the LHC is to allow us to build onto our current knowledge.

However, any theory that says the LHC is safe from creating mini black holes cannot therefore be 100% certain to be safe as the theories themselves are not 100% certain.

Therefore scientists cannot say its safe with 100% certainty.

So what concerns me more is the idea that scientists are claiming 100% certainty in its safety. That sounds at best more a political statement than science. And at worse, it shows the potential for flawed thinking on the part of the scientists who naturally wish to seek the goal of learning more.

We cannot know its truly 100% safe and we cannot know any percentage figure that gives the degree of its safety. Any such figure would be based on assumptions and feelings and not based on science.

Therefore while I deeply share the excitement and desire to discover and continuously learn all we can about science, I have to ask, is our desire to learn worth any risk? ... Especially as this risk isn't just person risk or even local risk, its potentially a global risk, so the stakes are as high as it can get. If we are wrong about the ability to create a mini black hole that proved to be sustainable, then in such an event, there would be no way to contain it or stop it.

Re:This is just a part of Large Hadron Collider

[Dread_ed]

"The black holes that are getting created here will not destroy the earth."

Suuuure! That's what you said the last time the Earth was destroyed.

Re:This is just a part of Large Hadron Collider

[flabbergasted]

Right so we have theories such as for example...

(1) Higher energy collisions occur in the atmosphere.

With point (1) we actually have an assumption which is a fair assumption,...

That's not an assumption. It's as well established a fact as any other in the world. See: Ultra-high-energy Cosmic Ray and its references to the primary literature. If you want to discount such evidence, you might as well forbid children from jumping on their beds because they're in danger of launching themselves into space since gravity is just an assumption.

For example we have a concentrated particle beam than would not occur naturally in our atmosphere

It's difficult to even know how to respond to such a statement. Are you concerned that the concentration of particles in the LHC beam is higher than in the atmosphere? It isn't. Are you concerned that particles in the LHC beam will somehow form an unruly mob and behave in a way that is different from the individual particles? They can't.

The only reason for using what you call concentrated beams is to reduce the mean time between interesting interactions to something which can be measured in a reasonable time. When an interesting interaction does occur, it is between a quark in a proton colliding with an (anti)quark in an anti-proton. The other quarks in those two particles have no influence on the collision, much less the other particles in the beam. Each event is completely independent of the others. There is no difference between shooting a million particles at a target once, and shooting one particle at the same target a million times. Statistically, you will end up with the same results. Or, put another way, you have the same probability of producing a particular interaction in both cases. It simply takes more time and energy to perform one experiment than it does the other.

And don't forget that the physics is independent of the inertial frame of reference. From the point of view of the ultra-high energy cosmic ray, someone fired the Earth in its direction at practically the speed of light! Now that's what I call a concentrated beam of particles! I doubt if CERN is going to be up to that task anytime soon.

We cannot know its truly 100% safe and we cannot know any percentage figure that gives the degree of its safety. Any such figure would be based on assumptions and feelings and not based on science.

Quite the opposite is true. It is your argument which is based on assumptions and feelings and not on science. Your objections are based on complete ignorance of the subject.

Re:This is just a part of Large Hadron Collider

[Iron Condor]

Suuuure! That's what you said the last time the Earth was destroyed.

According to the International Earth-Destruction Advisory Board (IDEAB) the current Earth-Destruction Alert Level (EDA Level) is "green" which indicates that the earth has not been destroyed. Furthermore, the Current Geocide Count (CGC) is zero, indicating that the earth has not yet been destroyed in the past. (In the event of the Earth being destroyed, the CGC will be increased by one, to read "1".)

You must thus be mistaken.

Re:This is just a part of Large Hadron Collider

[MindKata]

Ok, first, thanks for taking the time to reply.

As for my point (1) maybe I didn't explain myself clearly enough, as you have misinterpreted what I was saying. I was referring to the assumption of the kinds of particle collisions that can occur. I fully accept very high energy subatomic particles do occur in nature (although their frequency of occurrence isn't very high, (by high I mean we don't seen billions of very high energy particles per square micrometre every nano second (thankfully ;) but the occasional few definitely do occur).

However, we will have high concentrations of *high energy* particles in the LHC *in a very small space*

One thing I'm very interested in is the kinds of particles collision interactions that are possible.

For example, imagine two cars driving head on into each other while both are travelling at say 100 Mph ... and you get to see the collision in slow motion video from a side on (say 10 metre away) perspective. Now imagine watching the video as the two cars first start to crush and crumple up into each other, as they get squashed together and torn apart by the collision. Now imagine as these two cars are mostly though the process of crushing together and getting torn apart, that a 3rd car then slams into the back of one of the cars. (Or another two car collision occurs at the side of them and their debris is spraying into each other debris).

If this were a particle accelerator and the cars were particles, then the detectors would most likely pick-up an interesting (but less frequently occurring) collision.

The frequency of this kind of interaction is less than simpler two particle collisions, however its not impossible. So you end up with showers of debris and occasionally we my see something very interesting in the debris. That "something very interesting" event could be cause by rarely occurring types of collisions. And don't forget that the extra (3rd or more) "cars" don't need to hit the first two "cars" ... their debris can hit other debris etc..

So what if something dangerous was formed in one of these rare showers of collisions?

Also the whole point of particle accelerators is the beams are designed to focus into a small an area as possible, to maximise the chances of collisions.

Also Hawking radiation is not 100% proven as fact ... its still currently a theory and holes in that theory have been already suggested.
e.g. http://en.wikipedia.org/wiki/Trans-Planckian_probl em

Sorry

[Anonymous Coward]

Wow! That is beyond cool! It's supercool.

Re:Sorry

[tom17]

ed

Re:Sorry

[KDR_11k]

vi

Re:Sorry

[Vegeta99]

notepad.exe

Finally!

[gbobeck]

This is ultra exciting news... scientists have finally produced a magnet which is capable of holding an entire set of Encyclopedia Britanica to my refrigerator!

car theft

[Rulke]

if you install one onder your parking slot it will also prevent anyone from stealing your car

Shutdown

[Detritus]

How do you shutdown the magnet without destroying it? According to my rough calculation, it stores energy equivalent to about 500 kg of TNT.

Re:Shutdown

[KokorHekkus]

The electromagnet not used to hold anything together. The energy is just "stored" in the coils and when you remove the power supply the field dissipates. Now, should you short-circuit the coils - that would be interesting.

Re:Shutdown

[trip11]

There is about 1 GJ of energy stored in the magnet when it is at full strength. I don't remember my TNT converstions, but admitedly that is a lot. The energy is disapated through resistors and that heat is dumped into a LOT of mass all while actively cooling everything. Here is a pretty picture of the current as a function of time during the test (notice how fast it was shut down) http://jenni.web.cern.ch/jenni/BT.9Nov06.jpg/ The axis are in amps and minutes by the way. And yes, that is ~20,000 amps. As another intresting LHC note, the magnets in the accerator store ~11GJ of energy which is disapated into something like 50 tonns of steel. This is (breaking out the obscure unit conversions) the energy of something like 40 bullet trains traveling at full speed, or a nuclear aircraft carrier traveling at full speed. The energy stored in the actual beam of protons is also not anywhere near negligible and systems had to be designed to dump all of this energy as well.

Re:Shutdown

[Detritus]

One situation that I was thinking about was the case of a super-conducting magnet heating up and losing its superconductivity. I've read about MRI machines suffering expensive damage when they aren't shutdown properly.

Re:Shutdown

[KokorHekkus]

That is an interesting question. One way could be to use separate cooling systems for each coil and if there is a cooling system failure you could shunt the energy from the failing coil to the rest of them and then proceed with an orderly shutdown. Anyone else have any suggestions? (Or actualy *gasp* know? :)

Re:Shutdown

[tomstdenis]

All you have to do is shunt the power to a secondary plasma relay and then the induction coils will shut down normally.

Oh wait ... this isn't Star Trek?

Tom

Re:Shutdown

[Anonymous Coward]

Just reverse polarity!

Re:Shutdown

[p00ked]

Probably not a good question to ask Brainiac. http://www.skyone.co.uk/programmes/brainiac/

Re:Shutdown

[imsabbel]

I read about it years ago, so my memory is abit hazy.

But they do have extensive field-quench protection systems. (they need it, as its by far the biggest liquid helium installation in the world).

One way they protect themselvs is that they are well below the critical temperature for the magnet at the current density they use. They also use liquid helium evaporation cooled to about 2K. And they have huge venting tanks for quench protection.

The sublimation heat of helium is not that big, but they have 10s of tons of it to carry away the heat.

Re:Shutdown

[squoozer]

I once worked with a guy who used to maintain fairly large superconducting NMR magnets. According to him they procedure was essentially as follows Step 1: Connect wires to the magnet taking great care not to quench the magnet in the process (e.g. stop it super conducting). Step 2: Place a large resistive load between the wires and bleed off the stored energy.

Apparently you only screw up step one once.

Re:Shutdown

[bockelboy]

An increase of only a couple of degrees of temperature can cause massive, and I mean massive, problems. They expect to loose a couple of magnets here and there, but the loss of the detector would be devastating. Not only does the magnet get destroyed, but there's enough energy in the beam (which would no longer be focused) to punch big holes in walls. This is why it is fairly deep underground.

To guard against this (at least in the sister project, CMS), they have 4 huge tanks (about the capacity of two semi-trucks, or more) of liquid helium sitting right above ground. If there's ever an emergency loss of power, these will flood the magnets with liquid helium to protect the magnets.

There's a reason that this project cost $8 billion and is billed as the most complex scientific experiment in the history of man.

Re:Shutdown

[necro81]

The energy is just "stored" in the coils and when you remove the power supply the field dissipates. Now, should you short-circuit the coils - that would be interesting.

The coils are short circuited - each barrel toroid is a very large loop of superconductor. A circuit with no resistance is, almost by definition, a short circuit. But, because the coils are superconducting, the current in them flows without dissipating. You can disconnect the power supply, and the current still flows. That's the beauty of using superconductors to create large magnetic fields - once the current level is established, the magnetic field does not require additional energy input to exist (well, aside from the power to keep the coils at a superconducting temperature).

Re:Shutdown

[Rich0]

I believe the wires mentioned in step 1 lead to a small header coil that heats a very small section of magnet wire just above the critical temperature. The resistive load is then the section of magnet wire itself - which now is resistive. However, you wouldn't want to use a "large" resistive load. Standard NMRs run hundreds of amps so you don't want much resistance at all.

If you generate too much heat the situation goes exponentially out of control as the entire magnet rapidly heats up (as each portion of the wire heats it becomes resistive and generates even more heat). Almost instantly you vaporize all the coolant, and a hundred gallons of liquid He displaces a LOT of air when this happens. Basically you have to run for the door and hit the emergency ventilators fast, or you will collapse in a few 10s of seconds.

Haven't seen a quench firsthand but I know folks who have and it is quite an impressive site. I did walk past an NMR lab after a weekend quench and all the computer monitors had psychedelic color schemes.

Re:Shutdown

[trip11]

Stupid trailing slash on my URL

Try http://jenni.web.cern.ch/jenni/BT.9Nov06.jpg

Re:Shutdown

[njh]

How practical would this technology be for storing demand fluctuations in the grid?

Re:Shutdown

[Lost Race]

1 GJ is about a quarter of a ton of TNT. At least, that's what Wikipedia says.

Re:Shutdown

[arminw]

..... Now, should you short-circuit the coils - that would be interesting.....

Actually OPEN-ciruiting the coils would be much more fun. Such a magnet is a huge inductor and as such will want to keep whatever current is flowing in it constant through whatever resistance it can go through. If the circuit is opened, then there will be a monstrous arc through whatever path the current may find until all the energy stored in the magnetic field is dissipated.

Short circuiting such a superconducting coil would slowly release the energy into whatever resistance the external short represented. If the short were also superconducting, then the current would never decrease. A superconsducting jumper with a small heater can act as a switch to establish this short circuit across the coils after magnetic field is at its proper level. The heater is turned off to allow the jumper to become superconducting. The result is that the magnet will remain at full field as long as it and the shorting section are all superconducting. The power supply that originally ran the current through the magnet can now be switched off and disconnected. The magnet will now only consume whatever power it takes to run the refrigeration system that keeps it cold enough to remain superconducting. With good thermal insulation, that power can be quite small.

Re:Shutdown

[arminw]

.....Anyone else have any suggestions?.....

In practice there is a resistor connected across the coils. The value of this resistor is such that it is large in relation to the total resistance of the coils when these are NOT superconducting. Since the resistance of the coils is zero when it is superconducting, all the current from the power supply flows through the coils and nothing through the resistor.

If the magnet or any part thereof becomes too warm to remain superconducting, some electronics detects this and disconnects the power supply. The energy in the magnetic field is now dumped mostly into the resistor, but some of it also into the magnet itself. By choosing the value of the resistor correctly it is possible to protect the magnet itself from damage. After some time, the refrigeration system will cool the magnet back down to the temperature where it is once more superconducting and normal magnet operation can resume.

Re:Shutdown

[arminw]

....Basically you have to run for the door and hit the emergency ventilators fast, or you will collapse in a few 10s of seconds.....

Helium is lighter that air and immediately goes to the ceiling. All that will happen is that the people will sound like Donald Duck for a sort time after a large amount helium is released into a room. You will want to stay away from the jet of escaping helium however, as it is VERY cold and will instantly freeze any appendage that gets in its way.

Superconducting wire in all magnets is in parallel with normal copper wire in a sort of matrix of the superconductors imbedded in copper. The superconductors carry all the current normally, but if the superconductivity disappears, the copper safely carries the current for a short time. This in addition to an external resistor across the terminals of the coils keeps the magnet and people safe.

Re:Shutdown

[arminw]

.....This is why it is fairly deep underground......

Actually it is because of the huge amount of ionizing radiation (mostly x-rays) produced when any high energy particle beam hits stuff. When this machinery is operating, the many feet of earth act as cheap and effective shielding to keep the operators and scientists in the control rooms safe. The energy in the beam as such is actually quite small. Safely dumping 11Gj of energy stored in the magnetic field is a far bigger challenge.

Re:Shutdown

[infolib]

I've had this happen to me. Not in an MRI machine, but in a liquid He-cooled cryostat. (Oxford Instruments Spectromag)

The magnet is superconducting, but the small shunt completing the circuit is heated to become a normal conductor while slowly pumping current in through some big-ass copper cables. Now in this case the copper cable connector had not been plugged in well enough, and as the field reached about 3T, the copper heated and brought the circuit out of superconductivity. The energy stored in the field was dumped within a second or two and Helium spewed out of the safety valve in a neat display of boiling air. Cost some hours of work and about 20L of (expensive) liquid He.

The cryostat is built to handle this, but an MRI machine is bigger and often has a stronger field. If it doesn't have some well-designed safety valves it's easy to imagine the Helium bath blowing out.

Re:Russian maggnetts

[Anonymous Coward]

i'll pump hot grits up my ass

How Uncanny

[scotbot]

This morning I sensed a great disturbance in the Force, as if millions of floppy disks cried out in terror and were suddenly silenced!

What?

[Anonymous Coward]

Can i get a B.O. Wolf cluster of those??

Obligatory

[Anonymous Coward]

I, for one, welcome our new homosexual linus overlords.

Strength ?

[vikingpower]

I wonder what its strength is, in Tesla ? The article doesnot say that

Re:Strength ?

[tonicblue]

4

Apparently the Lameness filter has a problem with straight forward answers.

Oblig

[h2g2bob]

It was as though millions of credit cards suddenly cried out in terror and were suddenly silenced.

Re:Oblig

[legoburner]

aaahhh... that would be the reason they switched to chip-and-pin instead of the magnetic strip on European credit cards. Now it all makes sense!

Re:Oblig

[camperdave]

I can't figure out how to mod you up, so you'll just have to settle for kudos. Most Excellent post!

And in case you are wrong still,

[Anonymous Coward]

you have some anti-hydrogen at hand in CERN to destroy the black hole right - it being not much more than an incredible mass itself ?

Re:And in case you are wrong still,

[bheekling]

You do realise that an "incredible mass" when combined with an "incredible anti-mass" will probably cause enough energy to be released to destroy everything for several tens of kilometers? That said, they will be making *particles* collide. That means they will be working with at most a few kilojoules of energy. (taking into account their mass _and_ their Kinetic Energy)

Re:And in case you are wrong still,

[FusionDragon2099]

Hmmm... several tens of kilometers being destroyed or the whole Earth being swallowed in a black hole... hmmm....

Re:And in case you are wrong still,

[Anonymous Coward]

Trust me, CERN does not have enough anti-hydrogen on hand to destroy a square kilometer of anything. That stuff is very tough to make, it was only recently they even managed to make single atoms of it.

Mandatory reference...

[Anonymous Coward]

Imagine a beowulf cluster of...

Wait a minute... That's just a magnet

4 8 15 16 23 42

[nowonmai]

[EXECUTE]

Re:4 8 15 16 23 42

[f8l_0e]

It would seem that your joke was LOST on a lot of people.

ATLAS webcams

[fresita]

http://atlas.ch/webcams.html With images from when they began.

Ah ha!

[SnarfQuest]

That explains it! There I was, walking around in my suit of armor, when suddenly, WHAM! Stuck against the wall! And now, every time I pass the kitchen, the silverware shoots out at me!

Re:Ah ha!

[Nevtje(hr]

Walking around in your -what-?

Dude, I think you've been playing too much World of Warcraft.

World's Largest Supercooled Magnet Activated...

[compuguy84]

"World's Largest Supercooled Magnet Activated"

...that's what she said. ;)

Monitor Troubles

[8ball629]

This explains why my monitor has several strange rainbow patterns on it.

atleast with photo

[vincnetas]

http://news.nationalgeographic.com/news/2006/11/06 1121-giant-magnet.html

Field strength and other detials

[HalfFlat]

I was wondering what the magnetic field strength of this magnet would be, but the FA is a light on details. But there's a pamphlet!

Peak field strength for the barrel toroid magnet is 3.9 Tesla. And apparently it will take 30 days to cool the thing down with liquid helium to operating temperature.

Re:Field strength and other detials

[kickedfortrolling]

Isnt that quite weak in scientific terms?

Re:Field strength and other detials

[imsabbel]

Well, its not weak. Sure there are MUCH stronger ones, but usually at the cost of size.
There is even a 20T magnet 30 meter away from me right now, but the volume of the bore is only the size of a can of coke.

The energy density goes square with the flux, but linear with the volume, so the size makes the magnet quite special.

Re:Field strength and other detials

[kickedfortrolling]

Appriciated.. Im sure i remembered playing with a generator that came up with a few T, and was on a mobile trolley. Thanks for the reply :) Whats the size of the tube in this case? the article isnt the most technical

Re:Field strength and other detials

[Rich0]

For those not into magnets, 3.9 tesla isn't all that much - maybe bigger than a typical hospital MRI, but by NMR standards it is pretty small - NMRs go up to around 20 tesla or so, and experimental non-superconducting magnets have gone to 25-30T (or even higher for brief periods). The non-superconducting magnets aren't useful for NMR or a lot of other physics since they tend to fluctuate quite a bit - they use water-cooled electromagnets and a HUGE amount of electricity. I remember reading about one that heated hundreds of gallons of water per minute several tens of degrees C. The really big fields are created by using explosives to forcibly compess one of these large fields to get a much higher field strength, but obviously that is a one-time experiment that doesn't last long.

On the other hand, this magnet is very large in size. High-field NMRs often have bore sizes measured in cm. A hospital MRI is much lower in field strength but obviously needs a bigger hole in the middle - the open MRIs for those who are claustrophobic are even larger.

And that Atlas magnet would make a very nice MRI - you could stand up inside of it! I'm sure it is quite fun to shim the field though!

This confirms what I've been saying all along...

[Black.Shuck]

...the Universe is made of cornflour.

Everytime I read about particle accelerators

[Centurix]

I always think of this toy we bought our cat, it's like a round disc with a tube around the edge with ping pong balls in it and a few holes in the side so kitty can chase the balls around for minutes and minutes.

I imagine a group of scientists standing at one point next to the tube with a hole, waiting and watching.

Strongest magnetic field or Physically Largest?

[digitalderbs]

I work in NMR, and the largest routine fields we work with are 21.1 Tesla (1H:900MHz),and the Florida State U National High Field lab has a working 45 Tesla NMR, which to my knowledge has the highest field.

According to this article, the peak fields for this magnet are 3.9T; Is this the world's largest magnetic field, or just the largest magnet physically?

Re:Strongest magnetic field or Physically Largest?

[imsabbel]

largest, in size, and strongest by the amount of energy contained (think about it: its has 100s of m^3 with nearly 4T flux)

Re:Strongest magnetic field or Physically Largest?

[bockelboy]

The ATLAS detector is about 7 stories high and half a football field long. The other general purpose detector on the LHC is 5 stories high and only about 25 meters (I think) long. That's why it's called the "Compact" Muon Solenoid.

It's incredibly impressive when you stand next to CMS (that's the only one I've been to), so the size of ATLAS must be mind-blowing.

Re:Strongest magnetic field or Physically Largest?

[gregor-e]

I received email from Dr. James Gillies of CERN on this:

Dear Gregory,

I believe that the field of the ATLAS magnet is around 2 tesla, but the volume is vastly larger than an MIR magnet. Another experiment at CERN, which has a smaller volume than ATLAS has a field that reaches 4 tesla. In the LHC particle accelerator itself, the field in the magnets is around 9 tesla.

Regards, James Gillies

Re:Strongest magnetic field or Physically Largest?

[BJH]

The place I used to work at (Tsukuba Magnet Laboratory) used to have the world record for the strongest continuous magnet field, peaking at 37.3T - I didn't realise somebody had beaten that.

Thank God for this one!

[flyneye]

Here in the states the inappropriately revered Ex-president Bill Clinton shut down our programs to divert the funding into finding sluts and other social democrat concerns.

Article

[Anonymous Coward]

Covered in adverts (literally, so you can't read it) only about 100 words long and no picture. Let's not slashdot this sort of stuff.

Only .5T...

[ignatz]

I was down in the ATLAS experiment cave last week, and saw the detector. It's a massive piece of equipment, nearly filling a cavern that could contain the Notre Dame cathedral.

The magnets generate a field of 0.5 Tesla (not as much as the magnets that manage the beam, but still pretty hefty!).

1800 scientists

[drooling-dog]

...and engages 1,800 scientists from 165 universities and laboratories in 35 countries.

That's going to be quite an author list when they finally publish...

Re:1800 scientists

[bockelboy]

You haven't seen many papers in particle physics, have you?

Many times the author list is longer than the article itself.

Re:1800 scientists

[antispam_ben]

Authors: Alpha, Beta, Gamma, Omega, et. al.
Abstract: The Authors have discovered a method to control The Universe.

Re:1800 scientists

[Anonymous Coward]

1800 Scientists got Engaged??!??!

Now THAT'S Newsworthy!

in other news...

[fusion9290991]

A sudden recent increase in the homing pigeon population has experts at a loss...

A little help, please

[datablaster]

'scuse me...could somebody help me get off the wall over here? I think my belt buckle is causing the problem...

I live inside the ring...

[Paul Bristow]

My house is actually inside the circle made by the ring, albeit at ground level, not 100m down. So far, My computers still work, but I guess the HDD's could be gradually demagnetising a bit on each turn.

So far, so goo£%^$.... NO CARRIER

i live in the exact center of the accelerator.

[phitar]

so far, i cannot feel the force.

My guess: mass is just grav Lorentz residue

[Anonymous Coward]

You know the interpretation of magnetism as a residual component of electromagnetism that gets "left behind" because of relativity? Two particles moving with respect to each other will always inhabit slightly different spacetime frames, as a result of which any electromagnetic interaction between them is not symmetric in E and H components because if you move axially with respect to one then you're moving transversally with respect to the other, so the instantaneous "Lorentz contractions" differ.

Well, something similar probably applies to mass and gravitational waves as well, because there is an orthogonal element to forces when applied to spinning mass, as anyone who has played with a gyroscope has experienced. That implies that at relativistic speeds there will be a residue in the transversal component.

This is handwaving of course ... but in the absence of a full GUT or even an accepted scientific explanation of "What is mass?", it's a possibility.

Super Magnet

[C4st13v4n14]

This story makes me want to go watch an episode of 'Lost'

Except ofcourse...

[Anonymous Coward]

by injecting anti-protons into them...

Yeah, but...

[barry_the_bogan]

... will it hold little Billy's painting on the fridge?

Re:Yeah, but...

[antispam_ben]

Even better, it will hold the fridge to Billy's painting!

Antimatter

[Anonymous Coward]

The real question is how much antimatter can the LHC store?

Remember the "cancelled" (translation: militarised) Superconducting Supercollider in the US? (The reason CERN had to build the LHC so that the civilian science population would have access to a similar facility)

Then the fun question, once a significant amount of antimatter is stored, how do you shut it down? You don't: planetary deadman switch.

BOFH

[obsidianpoet]

Did anyone see the BOFH on the list of participants? I mean this is the worlds largest bulk eraser :) It would make him proud :)

HAY!

[PixelScuba]

My Watch!

I wonder how it stacks up against this one?

[bri_eh]

It's certified the worlds largest! http://www.sudftw.com/fridge.htm

Re. Shutdown... and Natural Gas

[cdn-programmer]

NG sells for about 8 bux per Gj at the moment. That is a lot of energy to waste... don't they know we have an energy crisis about to happen?

The solar panels on my friend's WestFailia produce about 50 watts. On a sunny day he might have to wait an hour or so before he can run his toaster.

Seriously - tyring to put energy units into perspective is very necessary since most people (/.'s excepted) don't have a clue.

I couldn't find "jenni". Alas!

Re:Re. Shutdown... and Natural Gas

[arminw]

.....tyring to put energy units into perspective is very necessary.....

In terms of energy cost, the amount stored in this 11Gj magnet would cost about $214 retail here in Oregon. That is quite a bit more than the average electric bill here. It comes to a little over 3000Kwh of electricity.

And they called the computing grids...

[shdwtek]

...Deep Thought

MRI machine damage

[cdn-programmer]

Ya.. I've heard this happens to NMR machines too.

Bad headline

[Anonymous Coward]

The headline does not say what it means.
"Supercooled" means cooled below equilibrium phase-transition temperature.
E.g. if one is very careful, she can cool very pure water below 0 deg C
without freezing it. This magnet is "superconducting" (no electrical resistance),
which also means it is quite cold (probably around 2 K), but it is not "supercooled".

Not only...

[zlogic]

Not only Vista, but super-magnets now require activation!
OMG!

Bad Headline? Welcome to Slashdot!

[antispam_ben]

[ this post intentionally left blank ]

Half true

[DerekLyons]

The electromagnet not used to hold anything together. The energy is just "stored" in the coils and when you remove the power supply the field dissipates.

A dissapating magnetic field is a moving magnetic field. What happens when you have a magnetic field is moving in relation to any conductors? That's right - you create a generator.
 

Obligatory

[Anonymous Coward]

Yeah, supercool,
But will it run Linux ?

When the aliens invaded...

[Anonymous Coward]

I hope Gordon Freeman is not employed there....

Not today...

[gowdy]

I was down there today... I thought it was last week but the article says the 9th November (I'm sure it is more accurate than my memory).

That explains.....

[Anonymous Coward]

That explains the most unusual sensation in my prince albert today.

Uncertainty principle

[Beryllium Sphere(tm)]

Everyone knows that you can't make perfect simultaneous measurements of position and momentum. There's another such measurement pair, energy and time.

You need time to make a completely accurate energy measurement. At very short time scales, energy levels can be uncertain enough to be large enough to create particles.

These are called "virtual particles", even though they're as real as any other sort, simply confined to a temporary quantum fluctuation.

If you think this sounds like hocus-pocus, you have a healthy skepticism, but when you do the math for particle interactions and include the virtual particles, it all works.

They're appearing and disappearing constantly, and sometimes people do call it a soup.

Re:Go fuck youttrselgf

[Sneakernets]

Then why visit the site?

health dangers

[boldra]

Since you certainly sound like your close to the project, I'm replying, although please excuse that it's a completely different topic.

I seem to remember hearing somewhere that extremely strong magnetic fields can have immediate health impacts. Something about the iron in the blood no longer being able to carry oxygen? I've tried finding something about it in google and wikipedia with no success. What I'd love to see is something like wikipedia's great page on "orders of magnitude (power)" or " Table of exposure levels and symptoms of Radiation Sickness".

atlas url http://atlas.ch/

[tobyvoss]

atlas url http://atlas.ch/