Manufacturing Bits: Dec. 19

Superconducting magnet record; X-ray metrology record.


Superconducting magnet record
The National High Magnetic Field Laboratory (MagLab) has broken another world record for magnets.

With a superconducting magnet, MagLab reached a magnetic field of 32 teslas. This is a third stronger than the previous record and more than 3,000 times stronger than a refrigerator magnet, according to MagLab.

Tesla, or T, is the measurement of magnetic field strength. Another measurement unit is called gauss. One tesla equals 10,000 gauss. A refrigerator magnet has a field of 0.01 T or 100 gauss, according to MagLab. The Earth’s magnetic field is about 0.5 gauss or 0.00005 tesla. An MRI scanner has a 1.5 tesla magnet.

At MagLab, magnets are used as scientific instruments. The magnets are cylindrical in shape with a hollow core. Researchers insert samples in the core to collect data. Magnets are used to study materials, chemical compounds and biological processes. These processes are revealed when a specimen is exposed to high magnetic fields.

There are two types of electromagnets–superconducting and resistive magnets. Resistive magnets use copper and silver as conductors. Recently, MagLab reclaimed the record for the strongest resistive magnet.

Superconducting magnets use special materials that carry current. Superconductors are materials that conduct electricity with perfect efficiency, according to MagLab. The record-breaking 32 T magnet was built using low-temperature superconductors called YBCO. They are composed of yttrium, barium, copper and oxygen. Oxford Instruments and SuperPower helped deveIop these technologies in partnership with MagLab.

One of the two YBCO coils used in the world-record 32-tesla all-superconducting magnet. (Credit: Stephen Bilenky)

“This is a transformational step in magnet technology,” said MagLab Director Greg Boebinger. “Not only will this state-of-the-art magnet design allow us to offer new experimental techniques here at the lab, but it will boost the power of other scientific tools such as X-rays and neutron scattering around the world.”

Laura Greene, MagLab’s chief scientist, added: “The new system, and the magnets that will follow, will give scientists access to insights never before possible. We expect it to break new ground in a variety of research areas. Physicists are especially excited about advances in quantum matter, which features new and technologically important ultra-thin materials, as well as exotic new states of matter in topological materials and complex magnetic materials.”

The 32 T is lowered into its cryostat, which keeps the instrument at a very cold operating temperature. (Source: MagLab)

X-ray metrology record
Deutsches Elektronen-Synchrotron (DESY), a Research Centre of the Helmholtz Association, has developed a new lens technology that enables X-ray microscopy with record resolution.

DESY and others have developed specialized X-ray optics, enabling them to achieve a focus spot size with a diameter of less than ten nanometers. This is about five times better than typical lenses.

X-ray metrology is used to explore complex materials. But developing an X-ray microscope that can resolve features below 10nm is a challenge. The X-rays themselves cannot be focused as easily as visible light, according to DESY.

One way to solve the problem is to use a specialized X-ray optic technology, which is called multilayer Laue lenses (MLLs). Unlike conventional optics, MLLs do not refract light, according to DESY. Instead, MLLs diffract the incident X-rays. This, in turn, focuses the beam on a small spot.

MLLs consist of alternating and thin layers of two different materials. Using a sputter deposition process, the new lenses consist of over 10,000 alternating layers of tungsten carbide and silicon carbide.

In the lab, researchers set up an experiment with the new optics at the Hard X-ray Nanoprobe experimental station at the National Synchrotron Light Source NSLS II at Brookhaven National Laboratory. The light source was used to focus an X-ray beam. The beam was focused in the vertical and horizontal directions. It has to pass through perpendicular lenses.

With the new X-ray lens technology, a spot size of 8.4nm by 6.8nm was measured with an efficiency of more than 80% “We produced the world’s smallest X-ray focus using high efficiency lenses,” said DESY scientist Saša Bajt. “These MLLs open up new and exciting opportunities in X-ray science. They can be designed for different energies and used with coherent sources, such as X-ray free-electron lasers. Since we now know how to optimize the lens design, our work paves the way to ultimately reach the goal of one nanometer resolution in X-ray microscopy.”

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