Switzerland winds up superconductivity

June 08, 2016

The unusual electronic properties of some superconducting materials permit lossless and dense electrical currents at very low temperatures, even in high magnetic fields. Conductors made of these materials are thus ideal for winding coils to generate very high magnetic fields, which are essential for a number of applications like magnetic medical imaging, magnetic resonance spectroscopy for the analysis of complex molecules or even accelerator magnets. To generate ever-higher magnetic fields, physicists at the University of Geneva (UNIGE) and an R&D team of Bruker BioSpin in Fällanden (ZH), both in Switzerland, started a collaboration in 2012, which was partially funded by the Swiss National Science Foundation (SNSF). Together, they successfully developed and tested the first superconducting coil able to reach a magnetic field of 25 Tesla. A first in Europe.

Today, the magnets used in nuclear magnetic resonance (NMR) and medical magnetic resonance imaging (MRI) represent the primary commercial applications of superconductivity. NMR, used mainly in the chemical and pharmaceutical industry, allows discovering new molecules, studying the structure of proteins or analyzing food content. It is essential for drug development or the quality control of chemical compounds. Modern measurement instruments available on the market today and manufactured particularly by Bruker BioSpin, world leader in this field, are able to produce magnetic fields of up to 23.5 Tesla. This limit is related to the physical properties of conventional superconducting materials used to generate the magnetic field. "However, there is a need for more powerful spectrometers in the biomedical field", says Carmine Senatore, professor in the Department of Quantum Matter Physics in the Faculty of Science at UNIGE. "Indeed, the stronger the magnetic field, the better the resolution of molecular structures. The goal of our collaboration was therefore to reach the new record for the magnetic field intensity of 25 Tesla with newly available superconducting materials, which was a real scientific and technological challenge. It is also an important milestone in the introduction of crucial technologies for the development of commercial ultra-high-field NMR products."

To create the magnetic field of 25 Tesla, the researchers combined a Bruker laboratory magnet producing 21 Tesla, already installed at UNIGE, with an innovative superconducting insert coil increasing the field by an additional 4 Tesla; so in total, a field well beyond the 23.5 Tesla reachable with conventional superconducting coils could be generated. In order to operate, the coil must be cooled with liquid helium to a temperature of ?269°C (4.2 K). The superconductor chosen to achieve such a field is a copper-oxide-based ceramic, YBCO. A one-micrometer thick layer of superconductor covers a thin steel tape which is then wound onto a cylindrical support to obtain the coil. 140 meters of 3 mm wide tape were necessary to produce the superconducting insert coil. In the preliminary design phase, many types of commercially available superconducting tapes were systematically studied and tested in order to understand and control their electrical, magnetic, mechanical and thermal properties. The challenge consisted of finding a conductor with the right balance of properties: it must carry high currents without dissipation, endure the winding process without degradation and withstand the magnetically generated mechanical stresses. This has been accomplished.

"In addition to the achievable higher resolution, which will certainly stimulate the scientific community and the network of institutions working at the forefront of molecular science, the use of YBCO will also simplify the operation of NMR spectrometers by using less complicated cooling systems", explains Riccardo Tediosi, manager of Bruker BioSpin's Superconducting Technologies group.

This first 25 Tesla coil will be a central and integral part of the laboratory of applied superconductivity at UNIGE. Although the coil is not a commercial product, the know-how developed for its design and manufacture represents an invaluable contribution to commercial NMR systems based on this technology. This project demonstrates how the Swiss network of research institutes and corporations active in this field in Switzerland are able to master such technologies. In the near future, this record magnet will be used for basic and fundamental research while scientists and engineers will aim at even more challenging goals: all-superconducting coils generating stable and homogeneous magnetic fields beyond 30 Tesla.
-end-


Université de Genève

Related Magnetic Field Articles from Brightsurf:

Investigating optical activity under an external magnetic field
A new study published in EPJ B by Chengping Yin, Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, South China, aims to derive an analytical model of optical activity in black phosphorous under an external magnetic field.

Magnetic field and hydrogels could be used to grow new cartilage
Instead of using synthetic materials, Penn Medicine study shows magnets could be used to arrange cells to grow new tissues

Magnetic field with the edge!
This study overturns a dominant six-decade old notion that the giant magnetic field in a high intensity laser produced plasma evolves from the nanometre scale.

Global magnetic field of the solar corona measured for the first time
An international team led by Professor Tian Hui from Peking University has recently measured the global magnetic field of the solar corona for the first time.

Magnetic field of a spiral galaxy
A new image from the VLA dramatically reveals the extended magnetic field of a spiral galaxy seen edge-on from Earth.

How does Earth sustain its magnetic field?
Life as we know it could not exist without Earth's magnetic field and its ability to deflect dangerous ionizing particles.

Scholes finds novel magnetic field effect in diamagnetic molecules
The Princeton University Department of Chemistry publishes research this week proving that an applied magnetic field will interact with the electronic structure of weakly magnetic, or diamagnetic, molecules to induce a magnetic-field effect that, to their knowledge, has never before been documented.

Origins of Earth's magnetic field remain a mystery
The existence of a magnetic field beyond 3.5 billion years ago is still up for debate.

New research provides evidence of strong early magnetic field around Earth
New research from the University of Rochester provides evidence that the magnetic field that first formed around Earth was even stronger than scientists previously believed.

Massive photons in an artificial magnetic field
An international research collaboration from Poland, the UK and Russia has created a two-dimensional system -- a thin optical cavity filled with liquid crystal -- in which they trapped photons.

Read More: Magnetic Field News and Magnetic Field Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.