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World's Largest Supercooled Magnet Activated

Zonk posted more than 7 years ago | from the my-watch-is-pulling-me-east dept.

171

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."

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171 comments

Might be painful (0)

Anonymous Coward | more than 7 years ago | (#16972118)

Hope no one with ferrous implants is around that thing~

Worlds largest bulk magnetic media eraser... (4, Funny)

binaryspiral (784263) | more than 7 years ago | (#16972128)

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.

Oblig (3, Interesting)

h2g2bob (948006) | more than 7 years ago | (#16972426)

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

Re:Oblig (4, Funny)

legoburner (702695) | more than 7 years ago | (#16972510)

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:Worlds largest bulk magnetic media eraser... (4, Funny)

Fred_A (10934) | more than 7 years ago | (#16972544)

No wonder I had to degauss this morning...

Re:Worlds largest bulk magnetic media eraser... (0)

Anonymous Coward | more than 7 years ago | (#16973394)

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

I live inside the ring... (2, Funny)

Paul Bristow (118584) | more than 7 years ago | (#16973586)

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

It's taking a long time (5, Funny)

BadAnalogyGuy (945258) | more than 7 years ago | (#16972136)

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

Re:It's taking a long time (1)

RuBLed (995686) | more than 7 years ago | (#16972158)

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 (0)

Anonymous Coward | more than 7 years ago | (#16972240)

Wooosh

why (3, Insightful)

tezbobobo (879983) | more than 7 years ago | (#16972148)

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 (4, Informative)

hcdejong (561314) | more than 7 years ago | (#16972210)

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 (2, Informative)

bmgoau (801508) | more than 7 years ago | (#16972470)

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 (4, Informative)

hcdejong (561314) | more than 7 years ago | (#16972586)

Actually, no. The LHA is not a cyclotron. In a cyclotron [wikipedia.org], 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 (3, Informative)

Gromius (677157) | more than 7 years ago | (#16972526)

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 (1)

Nanpa (971527) | more than 7 years ago | (#16972232)

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 [wikipedia.org]

Re:why (5, Informative)

Gromius (677157) | more than 7 years ago | (#16972316)

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 [fnal.gov] 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 (5, Informative)

romain wartel (918183) | more than 7 years ago | (#16972332)

> 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 [web.cern.ch]

> 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 [web.cern.ch]

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

Romain.

Re:why (2, Informative)

hcdejong (561314) | more than 7 years ago | (#16972396)

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 [wikipedia.org] is one of the detectors which use the output from the accelerator.

Re:why (1)

romain wartel (918183) | more than 7 years ago | (#16972582)

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 [web.cern.ch]

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 (1)

Anonymous Coward | more than 7 years ago | (#16972334)

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 (1)

Lord Crc (151920) | more than 7 years ago | (#16972724)

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 [atlasexperiment.org] 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 (0, Offtopic)

WhatAmIDoingHere (742870) | more than 7 years ago | (#16973152)

"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 (-1, Troll)

Anonymous Coward | more than 7 years ago | (#16973248)

With a .sig like

>Want a Catholic discussion board? Help me start it. [thecatholicrecord.org]

I guess there is no point telling you.

Here they come... (0)

Anonymous Coward | more than 7 years ago | (#16972150)

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

Impressive stuff (3, Interesting)

Hyksos (595814) | more than 7 years ago | (#16972170)

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

Re:Impressive stuff (1)

trip11 (160832) | more than 7 years ago | (#16972596)

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

The realy deep questions (4, Interesting)

Silver Sloth (770927) | more than 7 years ago | (#16972186)

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 (5, Informative)

tkittel (619119) | more than 7 years ago | (#16972336)

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 (1)

Silver Sloth (770927) | more than 7 years ago | (#16972492)

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 (2, Insightful)

myowntrueself (607117) | more than 7 years ago | (#16972864)

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?

Strongest magnetic field or Physically Largest? (1)

digitalderbs (718388) | more than 7 years ago | (#16972892)

I work in NMR [wikipedia.org], 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 [fsu.edu], which to my knowledge has the highest field.

According to this [zdnet.com] 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? (1)

imsabbel (611519) | more than 7 years ago | (#16973052)

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:The realy deep questions (1)

Mr2cents (323101) | more than 7 years ago | (#16973398)

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.

My guess: mass is just grav Lorentz residue (0)

Anonymous Coward | more than 7 years ago | (#16973738)

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.

Energy Consumption (2, Funny)

chriss (26574) | more than 7 years ago | (#16972188)

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 (5, Informative)

RuBLed (995686) | more than 7 years ago | (#16972244)

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 [web.cern.ch]

Re:This is just a part of Large Hadron Collider (5, Informative)

trip11 (160832) | more than 7 years ago | (#16972370)

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.

And in case you are wrong still, (0)

Anonymous Coward | more than 7 years ago | (#16972498)

you have some anti-hydrogen [wikipedia.org] 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, (1)

bheekling (976077) | more than 7 years ago | (#16973044)

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:This is just a part of Large Hadron Collider (0)

Anonymous Coward | more than 7 years ago | (#16972672)

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 (1)

MindKata (957167) | more than 7 years ago | (#16973728)

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 (1)

bmgoau (801508) | more than 7 years ago | (#16972552)

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 (1)

atria (788665) | more than 7 years ago | (#16973274)

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/ [aliceinfo.cern.ch] (home page of ALICE experiment) which is an experiment dedicated to study of Quark Gluon Plasma

My thoughts (-1, Troll)

Anonymous Coward | more than 7 years ago | (#16972268)

Russian maggnetts (-1, Troll)

Anonymous Coward | more than 7 years ago | (#16972326)

In soviet russia uncle fucks you!!!

Re:Russian maggnetts (0)

Anonymous Coward | more than 7 years ago | (#16972354)

i'll pump hot grits up my ass

What? (0)

Anonymous Coward | more than 7 years ago | (#16972390)

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

Obligatory (0)

Anonymous Coward | more than 7 years ago | (#16972418)

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

Go fuck youttrselgf (-1, Flamebait)

Anonymous Coward | more than 7 years ago | (#16972450)

slashcode sucks. it's full of troll holes. get your shit together you gay linux python perl google script kiddie bitches. [slashdot.org]

Finally! (1)

gbobeck (926553) | more than 7 years ago | (#16972278)

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 (1)

Rulke (629278) | more than 7 years ago | (#16972322)

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

Shutdown (4, Interesting)

Detritus (11846) | more than 7 years ago | (#16972346)

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 (2, Informative)

KokorHekkus (986906) | more than 7 years ago | (#16972446)

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 (2, Interesting)

Detritus (11846) | more than 7 years ago | (#16972578)

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 (1)

KokorHekkus (986906) | more than 7 years ago | (#16972656)

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 (4, Funny)

tomstdenis (446163) | more than 7 years ago | (#16972720)

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 (0)

Anonymous Coward | more than 7 years ago | (#16972780)

Just reverse polarity!

Re:Shutdown (1)

imsabbel (611519) | more than 7 years ago | (#16973060)

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 (5, Informative)

trip11 (160832) | more than 7 years ago | (#16972452)

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/ [web.cern.ch] 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.

World's Largest Supercooled Magnet Activated (-1, Redundant)

tttonyyy (726776) | more than 7 years ago | (#16972348)

...and I felt a great disturbance in the Force, as if millions of people with genital piercings suddenly cried out in terror and were suddenly silenced.

How Uncanny (1, Redundant)

scotbot (906561) | more than 7 years ago | (#16972372)

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

More about the ATLAS 830-ton magnet system (-1, Troll)

rpiquepa (644694) | more than 7 years ago | (#16972456)

ATLAS is a particle physics experiment which has been designed to analyze data gathered from CERN's Large Hadron Collider (LHC) scheduled to start its activity next year. One of the components of the ATLAS detector is its huge magnet system described in the CNET article. But read more for additional details and pictures [zdnet.com] of this gigantic magnet system.

Mandatory reference... (0)

Anonymous Coward | more than 7 years ago | (#16972508)

Imagine a beowulf cluster of...

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

I felt a disturbance in the Force.... (-1, Redundant)

Anonymous Coward | more than 7 years ago | (#16972538)

As if millions of floppy disks cried out,
and were no more.

Tired of coming unglued? (-1, Offtopic)

Anonymous Coward | more than 7 years ago | (#16972548)

See this! [stickdeath.com]

Re:Tired of coming unglued? (-1, Troll)

Anonymous Coward | more than 7 years ago | (#16972738)

your mother eats ass turds

Re:Tired of coming unglued? (-1, Troll)

Anonymous Coward | more than 7 years ago | (#16972836)

Offtopic? Go fuck yourselves

Ah ha! (3, Informative)

SnarfQuest (469614) | more than 7 years ago | (#16972684)

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!

World's Largest Supercooled Magnet Activated... (1)

compuguy84 (886540) | more than 7 years ago | (#16972714)

"World's Largest Supercooled Magnet Activated"

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

Field strength and other detials (3, Informative)

HalfFlat (121672) | more than 7 years ago | (#16972808)

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 [cern.ch]!

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 (1)

kickedfortrolling (952486) | more than 7 years ago | (#16973298)

Isnt that quite weak in scientific terms?

Re:Field strength and other detials (1)

imsabbel (611519) | more than 7 years ago | (#16973410)

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 (1)

kickedfortrolling (952486) | more than 7 years ago | (#16973504)

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

Everytime I read about particle accelerators (5, Funny)

Centurix (249778) | more than 7 years ago | (#16972886)

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.

Thank God for this one! (1)

flyneye (84093) | more than 7 years ago | (#16972932)

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 (0)

Anonymous Coward | more than 7 years ago | (#16973114)

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... (1)

ignatz (10191) | more than 7 years ago | (#16973208)

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 (3, Funny)

drooling-dog (189103) | more than 7 years ago | (#16973238)

...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...

A little help, please (1)

datablaster (999781) | more than 7 years ago | (#16973474)

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