Delft SEM tweak results in 20x faster imaging

Researchers at Delft University of Technology have found a cunning trick to enhance image processing speeds by as much as 20 times. The technique: apply voltage to the specimen holder. With this intervention, researchers found that they could speed up specimen imaging, which would normally take an electron microscope one week to complete, to as little as a single night or working day.

Two images of a HeLa cell, both recorded in 33.6 seconds. The one on the right was taken while a voltage was applied to the specimen holder. Credit: TU Delft

Electron microscopes are capable of magnifying objects up to a million times, enabling you to examine the structure of the tissue or other material at almost molecular level. But because the device works in such detail, it’s a scrupulous task to map out small objects. By applying a voltage to the specimen holder, researchers were able to slow down the incoming electrons while simultaneously accelerating the outgoing electrons. This acceleration means the electrons hit the detector with more energy, so they generate more signal, thereby overwhelming electronics noise and shot noise and enabling the device to measure more efficiently.

Perhaps the best aspect of this TU Delft trick is that it doesn’t require any complicated adjustments. Anyone with a scanning electron microscope can use it. “In most electron microscopes, it’s already possible to apply a voltage to the specimen holder. Normally people use this option to separate high-energy scattered electrons from those with low energy, so you’re only left with the useful signal,” says TU Delft researcher Jacob Hoogenboom. “But until now, no one had realized how much more quickly you can image your specimen.”

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