Brookhaven Lab researchers have explored a new class of superconductors called high temperature superconductors (HTS) that can operate at temperatures as high as 77 K, achieved by cooling with cheap, plentiful liquid nitrogen, or can create very high magnetic fields — more than 20 Tesla — when cooled to about 5 K.
Since 1969, scientists have been interested in the idea of colliding muon particles, which because of their unique properties, could reveal new physics. With the discoveries of a Higgs-like particle at the LHC, there has been renewed interest in a collider using muons because they would be well-suited to detailed studies of these particles.
However, several required technologies for muon colliders are not yet developed, according to Robert Palmer of the BNL Physics Department, who has been working on a muon collider for many years. One challenge has been to develop extremely high field superconducting magnets — 30 T or more — that are essential for achieving high luminosity, a term related to having a sufficient number of collisions.
For this purpose, the past achievements of Gupta’s group developing solenoid coils of 9 T and 16 T peak fields are very promising.
“In the next step,” said Gupta, “we will put the two record-breaking solenoids together and add a few more coils. If all goes well, we will reach more than 20 T.”
These magnets are being developed as a part of a collaboration with Particle Beam Lasers, Inc. through the Small Business Innovative Research program. The high performance conductor material is provided by SuperPower, Inc.
Gupta explained that reaching 20 T with HTS alone will be an important milestone in the technology. This, when combined with a solenoid of about 10 T made with conventional superconductors, offers a clear path to 30 T.
HTS Magnets in Other Applications
While successful development of HTS magnets is expected to revolutionize accelerator technology, it is likely to have a major impact on many other fields as well. These include magnetic levitated trains (Maglev), magnetic resonance imaging (MRI) and other medical uses, nuclear magnetic resonance, energy storage, and national security.
Another significant project for the group is the design, construction, and testing of a large, about 25 T HTS coil for a high energy density superconducting magnetic energy storage (SMES) system. In this project, the Magnet Division is working with scientists in the Condensed Matter Physics and Materials Science Department to develop SMES technology in partnership with industry. This, if successful, will create a SMES system with energy density considerably greater than has been previously possible.