SuperSTEM 2 Unveiled

A scanning transmission electron microscope unveiled this week can sharply image an atom at 20 million times its actual size. The nanotechnology instrument could pave the way for pioneering medical research and the creation of smaller and more powerful mobile phones and computers.

The SuperSTEM 2, or scanning transmission electron microscope (STEM), made its official debut Wednesday at the Science and Technology Facilities Council (STFC) Daresbury Laboratory near Warrington. The microscope was created through a collaboration of the universities of Liverpool, Glasgow and Leeds and the Daresbury Lab and was sponsored by the EPSRC (Engineering and Physical Sciences Research Council), the UK’s main agency for funding research in engineering and the physical sciences. It was built by Nion Co. of Kirkland, Wash.

Mhairi Gass of Liverpool University beside the SuperSTEM 2, a scanning transmission electron microscope that can image an atom at 20 million times its actual size. (Image courtesy STFC Daresbury Laboratory)

"Our society places huge value on making things smaller, cheaper, faster and more effective. This often requires the creation of new materials, new ways of making materials and the understanding of the atoms within them. The behavior of atoms can change, depending on the size of the particle they are in," said the University of Liverpool's Andrew Bleloch, PhD, SuperSTEM 2 technical director. "SuperSTEM 2 means that researchers can now study how these atoms behave in their 'native' form and how they might perform as components of different products that come into contact with human beings. An example of this would be how face creams or sun lotions work and how our bodies will react with the atoms found within them."

The SuperSTEM 2 works by scanning a beam that has been focused down to the size of an atom, across a sample, providing chemical information on the sample at the same time. Although scanning transmission electron microscopy has been used as a technique for some years, detailed imaging of atoms was previously impossible due to defects affecting all lenses. SuperSTEM 2 surpasses the abilities of traditional STEMs throught its inbuilt computer-controlled system that corrects these defects, much in the same way that glasses correct for vision problems.

The first SuperSTEM, SuperSTEM 1, was an existing STEM retrofitted with an aberration corrector. SuperSTEM 2 is the first dedicated SuperSTEM microscope. Both microscopes are capable of producing images of a specimen with a resolution of 1 angstrom (one ten-millionth of a millimeter) in diameter, but the new microscope allows an even greater degree of tilt, and electron energy loss spectra recorded from the specimen offers elemental and chemical data with atomic column detail, STFC said.

One of the key reasons the microscopes are housed at the Daresbury Laboratory is the incredibly stable geological conditions found in its sandstone bedrock foundation. That makes the new system so stable it would move no more than half a millimeter in 100 years, or 2000 times slower than continental drift.

SuperSTEM also has applications in medicine and is being used to aid understanding of diseases such as the inherited disease hemochromatosis, where the liver becomes overloaded with iron. The tiny particles that hold iron within the body are being examined as their structure will shed light on how iron is transported, stored and released in the body and why they become toxic to the body when there is too much of it.

The SuperSTEM 2 is also being applied to other projects, such as the development of advanced mountain bike tires and the next generation of computer chips for computers and cell phones.

For more information, visit: www.superstem.dl.ac.uk