Split magnet at Florida State University.
custom-built, $2.5 million “split magnet” system with the potential to
revolutionize scientific research in a variety of fields has made its
debut at the National High Magnetic Field Laboratory at Florida State
world-record magnet is operating at 25 tesla, easily besting the 17.5
tesla French record set in 1991 for this type of magnet. In addition to
being 43% more powerful than the previous world best, the new magnet
also has 1,500 times as much space at its center, allowing room for more
flexible, varied experiments.
offer some perspective on the strength of the new magnet, consider
this: Twenty-five tesla is equal to a whopping 500,000 times the Earth’s
magnetic field. Imagine that much power focused on a very small space
and you have some idea what the split magnet is capable of—and why
both engineers and scientists at the magnet lab are so excited.
Mag Lab has developed numerous world-record magnets; however, the split
magnet makes the largest single step forward in technology over the
past 20 years,” says Mark Bird, director of the laboratory’s Magnet
Science and Technology division.
decades, scientists have used high magnetic fields to probe the unusual
properties of materials under extreme conditions of heat and pressure.
There are unique benefits that arise at especially high magnetic fields— ertain atoms or molecules become more easily observable, for example,
or exhibit properties that are difficult to observe under less extreme
conditions. The powerful new split magnet system holds promise for even
more breakthroughs at the very edge of human knowledge.
new magnet was funded by the National Science Foundation and represents
years of intense collaboration between the lab’s engineering and
research teams, headed by scholar/scientist Jack Toth of the Magnet
Science and Technology staff.
magnet’s design required Toth’s team to rethink the structural limits
of resistive magnets—that is, those in which the magnetic field is
produced by the flow of electric current. The project required that the
engineers invent, patent and find sometimes-elusive builders for the
technology that could carry their idea through. The result of their
work, the new split magnet, features four large elliptical ports that
provide scientists with direct, horizontal access to the magnet’s
central experimental space, or bore, while still maintaining a high
research magnets are created by packing together dense,
high-performance copper alloys and running an electrical current through
them. All of the magnet’s forces are focused on the center of the
magnet coil—right where Toth and his team engineered the four ports.
Building a magnet system with ports strong enough to withstand such
strong magnetic fields and such a heavy power load was once considered
Interior parts for the split coil magnet were tested and retested to ensure the magnet’s structural integrity. Image: Florida State University
accomplish the impossible, Toth’s team cut large holes in the mid-plane
of the magnet to provide user access to the bore but maintain a high
magnetic field. All of this had to be done while supporting 500 tons of
pressure pulling the two halves of the magnet together and, at the same
time, allowing 160,000 amps of electrical current and 3,500 gallons of
water per minute to flow through the mid-plane. (The water is needed to
keep the magnet from overheating.)
the technological breakthroughs enabling the magnet’s construction are
important, the multidisciplinary research possibilities are even more
exciting. Optics researchers in chemistry, physics and biology are
poised to conduct research using the split magnet, while others are
optimistic about the potential for breakthroughs in nanoscience and
The magnet’s first user, a scientist from Kent State University, has already begun conducting experiments.
other research possibilities,” says Eric Palm, director of the magnet
lab’s Direct Current User Program, “the split magnet will allow optics
researchers unprecedented access to their samples, improve the quality
of their data, and enable new types of experiments.”