• Magnesium diboride (MgB 2) is also emerging as a new superconducting material for scanners and other magnetic instruments because of its much higher transition temperature (39°K). Cross section of winding from a superconductive magnet with NbTi multifiliments embedded in a Cu core.
• The most outstanding feature of a superconducting magnet is its ability to support a very high current density with a vanishingly small resistance. This characteristic permits magnets to be constructed that generate intense magnetic fields with little or no electrical power input.

The Large Hadron Collider (LHC) is currently operating at the energy of 6.5 TeV per beam. At this energy, the trillions of particles circle the collider's 27-kilometre tunnel 11,245 times per second. Before they reach the LHC, the particles are sped up in a series of interconnected linear and circular accelerators: once they reach the maximum speed that one part of the accelerator chain can achieve, they are shot into the next. Without any other force involved, the particles would drift apart and their momentum would carry them in a straight line. More than 50 types of magnets are needed to send them along complex paths without their losing speed.

Superconducting magnet technology has remained at the heart of Oxford Instruments throughout our history since being the company’s founding technology in 1959. As much as we are proud of this heritage, we do not rely upon it and we continue to bring our wealth of experience to every new opportunity and challenge.

All the magnets on the LHC are electromagnets. The main dipoles generate powerful 8.3 tesla magnetic fields – more than 100,000 times more powerful than the Earth’s magnetic field. The electromagnets use a current of 11,080 amperes to produce the field, and a superconducting coil allows the high currents to flow without losing any energy to electrical resistance.

Lattice magnets

Thousands of 'lattice magnets' on the LHC bend and tighten the particles’ trajectory. They are responsible for keeping the beams stable and precisely aligned.

Dipole magnets, one of the most complex parts of the LHC, are used to bend the paths of the particles. There are 1232 main dipoles, each 15 metres long and weighing in at 35 tonnes. If normal magnets were used in the 27 km-long LHC instead of superconducting magnets, the accelerator would have to be 120 kilometres long to reach the same energy. Powerful magnetic fields generated by the dipole magnets allow the beam to handle tighter turns.

When particles are bunched together, they are more likely to collide in greater numbers when they reach the LHC detectors. Quadrupoles help to keep the particles in a tight beam. They have four magnetic poles arranged symmetrically around the beam pipe to squeeze the beam either vertically or horizontally.

Superconducting Magnet Quench

Dipoles are also equipped with sextupole, octupole and decapole magnets, which correct for small imperfections in the magnetic field at the extremities of the dipoles.

Insertion magnets

When the particle beams enter the detectors, insertion magnets take over. Particles must be squeezed closer together before they enter a detector so that they collide with particles coming from the opposite direction. Three quadrupoles are used to create a system called an inner triplet. There are eight inner triplets, two of which are located at each of the four large LHC detectors, ALICE, ATLAS, CMS and LHCb. Inner triplets tighten the beam, making it 12.5 times narrower – from 0.2 millimetres down to 16 micrometres across.

After the beams collide in the detector, enormous magnets aid the measurement of particles. For example, physicists look at how charged particles bend in the magnetic field to determine their identity. Charged particles are deflected by the magnetic field in the detector, and their momentum can be calculated from the amount of deflection.

After colliding, the particle beams are separated again by dipole magnets. Other magnets minimize the spread of the particles from the collisions. When it is time to dispose of the particles, they are deflected from the LHC along a straight line towards the beam dump. A 'dilution' magnet reduces the beam intensity by a factor of 100,000 before the beam collides with a block of concrete and graphite composite for its final stop.

Insertion magnets are also responsible for beam cleaning, which ensures that stray particles do not come in contact with the LHC’s most sensitive components.

Superconductor Levitation

K&J experiments with superconductors, liquid nitrogen, neodymium magnets and levitation. While playing with liquid nitrogen isn't always practical for at-home science experiments, superconductors sure are neat!

What is a superconductor?

How Do Superconducting Magnets Work

A superconductor is a material that offers no electrical resistance and expels magnetic fields. All known superconductor materials are solids, and only exhibit superconducting properties when cooled to very low temperatures.

With the Type II superconductors used in these experiments, the magnetic field is ejected because of the Meissner effect. Depending on how deep you want to go into the physics of this, read more about the Meissner effect and Quantum Mechanics to learn more.

Why do we need to use liquid nitrogen?

When superconductivity was discovered back in 1911, known superconductors had to be cooled to almost absolute zero (0 K or -273C). Virtualbox on mac big sur. The first known superconductors had to be cooled below 10K (-263C) to exhibit superconducting properties.

NOTE: When talking about temperatures this low, the Kelvin scale is often used. The temperature in degrees Kelvin is simply the Celcius temperature plus 273.15. For example, a room temperature of 20C is 293.15K.

In 1986, the first 'high temperature superconductor' was discovered, for which the Nobel Price in Physics was awarded in 1987. Note that 'high temperature' is a relative term here. Yttrium-barium-copper-oxide, or YBCO, still must be cooled to below 93K (-180C) to act like a superconductor.

Conveniently, YBCO was the first superconductor that can be cooled with liquid nitrogen, which boils at 77K (-196C). This allows for (relatively) easier experimentation and use than previous superconductor materials.

That's why all the superconductors shown here are covered in liquid nitrogen -- to keep their temperature down at 77K (-196C), below the critical temperature at which they start acting like a superconductor.

Magnets can levitate over superconductors! Or superconductors can levitate over magnets!

The video below shows a ring magnet levitating over a series of superconductors arranged in a disc.

This next video below shows a superconductor 'train' floating over a bed of neodymium magnets. The train consists of a styrofoam box that contains two superconductor discs, with liquid nitrogen covering them. The track is made of nine BZ084 magnets.

(Special thanks to the folks from Air Products who helped us with the liquid nitrogen, nitrogen safety, and overall liquid nitrogen know-how.)

Why do they levitate? How does it work?

Superconductors repel magnetic fields due to the Meissner effect. Near the surface of the superconductor material, small currents flow (without any resistance) that make an opposite magnetic field that repels the field from the magnet.

We found that it doesn't behave like a pair of magnets repelling one another. With two magnets repelling, the force varies with how far apart the two magnets are. The closer the magnets, the greater the force.

With the superconductor, we could get levitation to happen 1/8' away or 1/4' away equally well. We also had to hold it there for a moment to get it stable. Why does it levitate in a stable way? Why doesn't the repulsion simply keep pushing away like a pair of magnets would? We found that flux-pinning is a good explanation.

What is flux-pinning?

In the magnetic field diagram shown, the magnetic lines of flux flow from the north pole to the south pole, and do not penetrate the superconductor at all.

At a tiny, microscopic level, there are imperfections in the superconductor. These allow a tiny amount of flux to get through the superconductor, and flow out the other side. These small flows of flux through it is enough to stabilize the superconductor, holding it in place.

See another video explanation of flux pinning here.

Warnings -- don't try this at home!

Here at K&J Magnetics, we're used to warning folks about how strong neodymium magnets can be. Liquid nitrogen comes with a new set of warnings to be mindful of. Lacking experience, we experimented with liquid nitrogen with the help of some folks from Air Products, who are quite experienced with handling this incredibly cold product.

If you experiment with liquid nitrogen, please consult an expert for compete safety instructions. Seek help. Don't try this alone. Windows 8 9200 activator downloadpartnersclever. Some pointers we observed:

• This is not a good grammar-school science experiment. Liquid nitrogen is not a toy!
• Liquid nitrogen can cause terrible burns. Death of living tissue happens quickly at these temperatures. Wear safety goggles, proper gloves, pants or apron that covers the shoes, etc. Removing jewelry and making sure none gets on top of or down in your shoes is a big concern.
• Liquid nitrogen must be stored in a way that allows it to vent. If sealed, it will explode. There are all sorts of specialized containers for handling it.
• Use in a well ventilated space. The evaporating nitrogen displaces oxygen, so you could axphyxiate from lack of oxygen. Since nitrogen is odorless, there is no warning.

Superconducting Magnets For Sale

Sorry, we don't sell superconductors.

If you are interested in more accessible levitation experiements, see our recent article on Diamagnetism and Levitation.

Superconducting Magnetic Energy Storage