Round strand superconductor Bi2212 with 0.8 mm diameter (courtesy of Nexans).
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Physicists and engineers have always been intrigued by high transition temperature superconducting materials ever since their discovery in 1986 by Bednorz and Muller. These materials offer new prospects for the SACM. Not only is their ability to transport an intensive electrical current at superconducting state preserved at temperatures in excess of 60K (for certain materials), but most importantly they keep their superconducting properties with an induction of 30T, providing they are kept at the temperature of liquid helium. Thus it becomes possible to make superconducting magnets that function between 30 and 40K or produce magnetic fields of 30T.
In addition to the modernisation of the test facilities, where tests on these new superconductors are conducted, the SACM, with the help of an industrial group, has begun development on the construction of a round strand that can be wired, and the research of applications requiring the use of magnetic fields higher than 20T.
The developments of conductors are focused on measuring the performance of the existing ribbons, particularly for use in fusion tokamaks. A joint study carried out with the Department of controlled fusion research at Cadarache sets out to qualify Bi2212 superconducting compounds and to study the consequences of their use in the operation of a machine such as the demonstration fusion reactor, Demo.
Applications identified as requiring magnetic fields higher than 20T are high field nuclear magnetic resonance (NMR) and magnetic levitation. High field NMR makes it possible to analyse the structure of complex molecules; it is currently thought that 20% of unknown molecular structures could be decrypted with instruments which function at the resonance frequency of a 1GHz proton, corresponding to a magnetic field of 23.5T. Magnetic levitation makes it possible to overcome the earth's gravitational pull in a paramagnetic or diamagnetic environment, and to recreate the conditions of experiments onboard spacecraft. This technique allows us to obtain better crystallographic purity in the development of crystals, to study anomalies in wettability phenomena and changes to self-organisation phenomena in biology or heat exchanges in walls.
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Dernière mise à jour : Jan 11th, 2024
