Discovery could help scientists better understand exotic behaviors of electrons.
This week at the lab, we retired a 1990 Toyota and are parking a 2016 Mercedes in its spot.
That's the metaphor offered by Bryon Dalton, head of operations for the lab's DC Field Facility, for a big upgrade of the lab's world-record 45 tesla hybrid magnet: a new set of 3,500-pound vacuum pumps.
Good-bye roll-down windows and Bush Sr.-era fuel economy. Hello turn-by-turn navigation, Bluetooth wireless data link and 10-way power driver seat.
The $260,000 German-made vacuum pumps will improve reliability and performance, generate systems diagnostics, and allow staff to run the pumps remotely. "You're going to have a better feel for what's going on and better control over it," said Dalton.
The pumps play a critical role in the operation of the hybrid, which pairs a resistive magnet with a superconducting magnet of niobium-tin and niobium titanium that requires temperatures near absolute zero. Helium liquefied on site has a temperature of 4.7 Kelvin, making Plutonian weather seem tropical by comparison. By dropping that liquid helium to below atmospheric pressure, the vacuum pumps, used with a special cooling apparatus called a Joules-Thompson refrigerator, gets it down to 1.6 Kelvin. This turns it into a zero-viscosity "superfluid" and maximizes the hybrid's efficiency.
Photo by Stephen Bilenky, text by Kristen Coyne.
This week at the lab, engineers are winding a coil for a new, hybrid magnet system that will match the field strength of our own world-record magnet.
Two teams from two magnet labs located on two continents have joined forces on this project.
The High Field Magnet Lab (HFML), located in Nijmegen, the Netherlands, is building a continuous-field magnet designed to generate a field of 45 tesla, which will tie the record now held by the MagLab’s 45 tesla hybrid magnet. The National MagLab is lending its expertise to the effort by building the superconducting portion of the magnet; the HFML is building the resistive portion.
In the end, five spools of cables containing a total of 2 km of superconducting wire will be joined and wound to form a 5-ton coil. The winding process alone requires several months. “Electrically you have to continue that path from one length of conductor to the next,” said MagLab engineer Iain Dixon, who is heading up the project. “There’s a lot of care and a lot of checks that go on to make sure that the bends are in the right place and the cuts are in the right place."
The inter-lab collaboration has meant a lot of back and forth for both teams. Andries den Ouden, head of superconducting magnet technology at Nijmegen, was in Tallahassee recently.
"During the project operation, there are no walls between the two labs," said den Ouden. "There's an open exchange of information … I think that's one of the key benefits."
Text by Kristen Coyne / Photo by Stephen Bilenky.
Nicolas Doiron-Leyraud of Canada's Université de Sherbrooke talks about his recent experiments on cuprate superconductors, why he chose physics over philosophy, and what makes the MagLab a great place to do science.
New kind of quantum Hall state observed in graphene superlattices.
Examining the material samarium hexaboride, scientists discover seemingly contradictory properties and an exciting, new mystery for physicists.
Researchers working at the National MagLab have identified a material that behaves as a conductor and an insulator at the same time, challenging current understanding of how materials behave, and pointing to a new type of insulating state.
A team of researchers from Université de Sherbrooke, Laboratoire National des Champs Magnétiques Intenses (LNCMI), University of British Columbia, Canadian Institute for Advanced Research and the National High Magnetic Field Laboratory discovered a previously unobserved portion of the Fermi surface in underdoped YBCO. This discovery provides further evidence to support the picture of the Fermi surface being reconstructed as a result of charge density wave order developing in underdoped YBCO prior to the material entering the superconducting state at lower temperatures.
Scientists using MagLab magnets bolster theory that quantum fluctuations drive strange electronic phenomena.
SmB6 has been studied for a number of years and its observed behavior had presented investigators with a conflicting set of observations that resisted explanation until recently. The observation of quantum oscillations by Li et. al. in what is a bulk insulator confirm that SmB6 becomes a topological insulator at low temperatures. A topological insulator is a material that develops a unique quantum mechanical state on its surface, which allows electrons to flow in a fashion similar to a metal.