Post by swamprat on Jun 17, 2019 14:11:09 GMT
This little superconducting magnet, about the size of an empty toilet tissue roll, helped the National MagLab achieve a world-record 45.5-tesla magnetic field. Source: National MagLab
MagLab’s test magnet is tons smaller but with same power
Byron Dobson, Tallahassee Democrat USA TODAY NETWORK – FLORIDA
June 17, 2019
The strongest, continuous-field magnet in the world is MagLab’s heralded 45-tesla hybrid instrument, which weighs 35 tons and has held the record since 1999. Source: Tallahassee Democrat files
The National High Magnetic Field Laboratory at Florida State University has made a big discovery in a small package.
A team led by FAMU-FSU College of Engineering associate professor Seungyong Hahn created a miniature magnet that generated a world-record 45.5-tesla magnetic field, the university announced Wednesday. The team’s work was published Wednesday in the journal Nature.
To put it in context, hospital MRI magnets generate about 2 or 3 teslas, and the strongest, continuous-field magnet in the world is the MagLab’s heralded 45-tesla hybrid instrument, weighing 35 tons, which has held the record since 1999.
The new 45.5-tesla magnet was a test magnet, offering a promising proof of concept. It is a different design from the 45-tesla magnet, which the lab has had for several years.
Researchers hope to continue to develop this technology, which is much more compact, into the next generation of powerful magnets.
The newest high-field magnet is wrapped into a coil that can fit inside a purse. It is considered a breakthrough in research in the fields of medicine, nuclear projects and medical research.
It weighs less than a pound.
“We are really opening a new door,” said Hahn, a researcher at the MagLab. “This technology has a very good potential to entirely change the horizons of high-field applications because of its compact nature.”
Think of the first brick-sized handheld cellular phones, compared to today’s smartphones tucked in rear pockets.
“This is indeed a miniaturization that could potentially do for magnets what silicon has done for electronics,” said National MagLab Director Greg Boebinger. “This creative technology could lead to small magnets that do big jobs in places like particle detectors, nuclear fusion reactors and diagnostic tools in medicine.”
Both the 45-T magnet and the 45.5-T test magnet are built in part with superconductors, a class of conductors boasting special properties, including the ability to carry electricity with perfect efficiency, according to the release.
The superconductors used in the 45-T are niobium-based alloys, which have been around for decades. But in the 45.5-T prototype magnet, Hahn’s team used a newer compound called REBCO, or rare earth barium copper oxide.
REBCO can carry more than twice as much current as a same-sized section of niobium-based superconductor.
This current density is crucial: After all, the electricity running through an electromagnet generates its field, so the more you can cram in, the stronger the field.
Also critical was the specific REBCO product used – paper-thin, tape-shaped wires manufactured by SuperPower Inc.
MagLab chief materials scientist David Larbalestier, who is also a professor at the FAMU-FSU College of Engineering, recognized the potential to pack more power into a potential world-record magnet, and encouraged Hahn to see what could be created.
The other key ingredient was not something they put in, but rather something they left out, FSU said.
Today’s electromagnets contain insulation between conducting layers, which directs the current along the most efficient path. But it also adds weight and bulk.
The mini magnet is built without insulation.
In addition to yielding a sleeker instrument, this design protects the magnet from a malfunction known as a quench. Quenches can occur when damage or imperfections in the conductor block the current from its designated path, causing the material to heat up and lose its superconducting proper milestone But if there is no insulation, that current simply follows a different path, averting a quench.
“The fact that the turns of the coil are not insulated from each other means that they can share current very easily and effectively in order to bypass any of these obstacles,” Larbalestier said.
The latest discovery brought accolades from the National Science Foundation, which has provided millions of dollars to the Tallahassee lab.
“When NSF first launched the National High Magnetic Field Laboratory decades ago, it revolutionized the use of powerful magnets for research,” said Linda Sapochak, director of NSF’s Division of Materials Research. “In announcing their new world-record breaking magnet, NHMFL has shown it continues to drive the cutting edge of this field, and the breakthroughs that will follow.”
Source: Tallahassee Democrat newspaper