Electrons, Cameras, Action!
Upgrade of electron microscopy cameras offers cleaner, more-efficient imaging data at the CNSI
The California NanoSystems Institute at UCLA has changed or added five cameras connected to its suite of six transmission electron microscopes. Taken together, the upgrades will dramatically reduce noise in imaging while increasing efficiency and offering options to meet the distinct needs of different types of investigations. These instruments are available to users from UCLA and beyond at the EICN.Researchers in a variety of fields, from biology to materials science, rely on transmission electron microscopy to explore details and phenomena invisible to optical microscopes. Too often, though, traditional CMOS and CCD cameras can lead transient events being missed due to pixel read noise and inefficient electron detection. “With scintillator cameras only part of the image is reproduced in the chain of events involved in detecting electrons,” said Matthew Mecklenburg, Director of the Electron Imaging Center for NanoMachines, a CNSI Technology Center.
In response to this problem, users at the EICN now have access to direct electron detecting cameras on all three of its field-emission-sourced instruments, the Titan 80-300, Titan Krios and TF20. With these state-of-the-art cameras, electrons are counted one-by-one and are only affected by the shot noise in the illuminating electron beam. The detectors improve the ability to reveal information out to single angstrom periodicities and improve the contrast acquired in an image to almost maximal efficiency.
“Electron counting cameras have revolutionized electron microscopy of biological structures,” said Matthew Mecklenburg, “and their high speed and increased sensitivity can also be a benefit for in situ TEM experiments, imaging of radiation sensitive materials, and high-resolution imaging.” The EICN’s Tecnai series of microscopes has gained two 16-megapixel CCD cameras — a Gatan Ultrascan for the T20 and a TVIPS TemCam F415MP for the T12 Cryo. In addition, a Gatan K2 direct electron-counting camera has been moved to the TF20. To the Titan series, the EICN has added a 4-megapixel CCD camera and a 64-megapixel camera, the Direct Electron DE-64.
“This camera will reveal the elusive atomic structure of radiation-sensitive materials and their nanoscale interfaces (e.g., lithium metal batteries, carbon-capture porous materials) that are critical for our transition to clean energy technologies,” said Yuzhang Li, assistant professor in chemical and biomolecular engineering.”The direct electron cameras have a linear mode and counting mode. The linear mode allows for higher fluence to facilitate imaging of materials science samples that are not sensitive to electron dosage. The counting mode operates at a limited fluence to prevent coincidence loss on a pixel and in this mode radiation-sensitive samples can be imaged to the highest degree of efficiency.
EICN has sustained its operations through the pandemic, although applications to use its equipment must comport with campus guidance designed to help control the spread of the coronavirus. Investigators interested in using the upgraded cameras can contact firstname.lastname@example.org.