8.3 Tesla Superconducting Magnet

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TheMagLab has seven user facilities located across our three campuses. Every year more than 1,800 researchers use our facilities - most at no cost to them - and publish more than 400 peer-reviewed publications.

The MagLab is home to the Magnet Science & Technology (MS&T) group and the Applied Superconductivity Center (ASC). Together, these groups work to develop powerful magnet technology and the strongest superconducting magnets in the world.

The largest and highest-powered magnet lab in the world, the National MagLab hosts more than a thousand visiting scientists a year. Researchers use our facilities for free, advancing understanding of materials and new technology, energy, health, the environment, and even the universe.

Developed in-house at the Magnet Lab, this magnet represents a major step forward in the development of superconducting magnets, the previous record was 24T, towards the goal of ever higher magnetic fields with dramatic reduction in energy consumption (kW vs MW) compared to conventional water-cooled resistive magnet technology. A lower noise environment for high precision measurements, as well as a larger sample space size provide additional advantages to this technology.

The magnet can house either a VTI or a top loading dil. fridge. The VTI enables temperatures in the range 1.4K - 300K with a 27.5mm sample space. The dil. Fridge has a base temperature of 14mK and cooling power of 400microW at 100mK with a 25mm sample space.

For decades, the world record for a superconducting magnet inched forward incrementally. But this giant leap to a 32 telsa superconducting magnet is bigger than all the improvements made over the past 40 years combined and represents a milestone in high-temperature superconductivity, a phenomenon first discovered in the 1980s.

The magnet is built with all-superconducting materials, and leverages two different types of superconductors to achieve its whopping field: a commercial low-temperature component from Oxford Instruments and two high-temperature coils that look like pancakes. At the center of those pancake coils are miles of flat wire YBCO (yttrium, barium, copper and oxygen) created by SuperPower Inc. in partnership with MagLab researchers. Scientists and engineers worked for years to develop the tricky material, which is electrically and mechanically completely different than its low-temperature counterparts. New techniques had to be developed for insulating, reinforcing and de-energizing the system.

Now, the 32 T system is providing researchers with a very stable, homogenous field suitable for sensitive experiments in nuclear magnetic resonance, electron magnetic resonance, molecular solids, quantum oscillation studies of complex metals, fractional quantum Hall effect and other areas.

In 2022, engineers and technicians from the National High Magnetic Field Laboratory were recognized with an R&D 100 Award for the design and construction of the 32 T. The R&D 100 recognizes revolutionary ideas in science and technology.

Dr Guillamn and her team will also build a microscope for these international facilities, improving the capacity of these facilities in the field of microscopy. Microscopes with high magnetic fields allow the direct visualisation of the electronic correlations, necessary to give conclusive answers to questions of Condensed Matter Physics, in fields such as graphene, nanotechnology, superconductivity or magnetism. Within the framework of this project, the origin of high-temperature superconductivity will be investigated by studying new iron-based superconducting materials.

In September 2018, the National Science Foundation (NSF) awarded $4.2 million to the National MagLab to launch a research and development effort for the next generation of high-field superconducting magnets. The goal is to create a magnet with a 34-mm bore and capable of generating a field of 40 teslas, which is 8 teslas stronger than the existing world-record superconducting magnet recently completed at the MagLab.

Superconducting magnets feature two increasingly important advantages over resistive magnets, including the MagLab's 45-tesla hybrid magnet. The first is their virtually limitless time at peak magnetic field. The MagLab's user community is finding it increasingly necessary to perform experiments at fixed high magnetic fields for extended periods of time while other experimental parameters are being tuned to probe the physical phenomenon of interest. This ability to "sit" at high fields is critical, for example, in spectroscopic studies that range from the traditional (optics and tunneling) to the more recently developed multiple-gate spectroscopies used to tune electron interactions in low dimensional materials. These and other experiments, like angular-dependence studies, pressure-dependence studies, and mapping of complex phase diagrams, often span a multi-dimensional phase space that demands long times at peak magnetic field.

Future high-energy accelerators will need magnetic fields of 20 Tesla and above. In order to achieve this level of performance, a new technological leap is required after niobium-titanium (NbTi) and niobium-tin (Nb3Sn) technologies have reached their practical performance limits. The magnets of the future will most probably be manufactured from high-temperature superconductors (HTS).

Not only can HTS conductors retain superconducting behaviour up to around 100 Kelvin, but they can also bear a magnetic field much higher than 20 Tesla, which is the main factor of interest for the accelerator magnets of the future. Because the critical temperature is so high, the material has a very large operating margin, which is beneficial to avoid quenching and to increase the reliability of the magnet.

To explore the use of high-temperature superconductors in high field accelerator magnets for future particle accelerators, in 2013 CERN partnered with a European particle accelerator R&D project called EuCARD-2. The project involved 40 partners from 15 European countries including CEA (FR), KIT (DE), University of Geneva (CH), University of Twente (NL) and Bruker HTS (DE). The aim of the project was to develop an HTS accelerator-quality demonstrator magnet, called Feather2, able to produce a standalone field of 5 Tesla, and between 17 and 20 Tesla when inserted into the Fresca2 high-field magnet. The first Feather2 magnet was built using an initial version of HTS conductor based on tapes of rare-earth barium-copper-oxide (generally referred as ReBCO). This was tested during the summer and achieved a standalone field of over 3 Tesla. The next magnet, based on high-performance ReBCO tape, is expected to exceed the 5 Tesla target by a significant margin, possibly approaching a field of 8 Tesla.

Is there a more rewarding thrill than to break a record? Whereas most of us must content ourselves with breaking personal bests, earlier this month the scientists and engineers of Berkeley Labs Superconducting Magnet Group experienced the rush of shattering a world record. The teams newest niobium-tin dipole electromagnet reached an unprecedented field-strength of 14.7 Tesla. This is more than 300,000 times the strength of Earths magnetic field.

"Our job is to push the technology envelope as far as we can in terms of high magnetic field strength and that is what we have done," says Steve Gourlay, a physicist with the Accelerator and Fusion Research Division (AFRD) who lead the team that designed and built the new champion.

Dubbed RD-3, the new world record-holding magnet is one meter long and weighs several tons. It consists of three magnetic coil modules (a double-pancake outer and single-layer inner) which were wound from more than eight miles worth of niobium-tin wire. The previous record field strength for a dipole electromagnet was 13.5 Tesla. It was set in 1997 also by a niobium-tin electromagnet designed and built here at Berkeley Lab.

Members of the new record-holding team in addition to Gourlay were Robert Benjegerdes, Paul Bish, Doyle Byford, Shlomo Caspi, Daniel Dietderich, Ray Hafalia, Charles Hannaford, Hugh Higley, Alan Jackson, Alan Lietzke, Nate Liggins, Alfred McInturff, Jim O'Neil, Evan Palmerston, GianLuca Sabbi, Ron Scanlan, and James Swanson.

Dipole magnets are used to bend and maintain the path of accelerating particle beams. The higher the field strengths of the magnets, the tighter the arc of the beam. With stronger dipole magnets, an accelerator can push particles to much higher relativistic energies around the same-sized circular beam path.

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