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Manufacturing Bits: Aug. 31

X-ray nanotomography; X-ray combo; China’s X-ray efforts.

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X-ray nanotomography
The U.S. Department of Energy’s (DOE) Argonne National Laboratory has developed a new method for improving the resolution of hard X-ray nanotomography.

In general, tomography involves a system, which takes images or cross sections of a sample using X-rays or ultrasound. The images are then re-created in the form of a 3D model.

One common form is called micro-computed tomography, which uses X-rays to create a 3D image composed of planar images, according to PerkinElmar. It’s often referred to as 3D X-ray, microtomography, or microCT imaging. “It’s similar to CT scans performed in hospitals but on a smaller scale and offers greatly enhanced resolution,” according to PerkinElmar.

Nanotomography is X-ray imaging on the scale of nanometers. The problem with X-ray nanotomography is that the spatial resolution has not improved in many years, according to Argonne National Laboratory.

In response, researchers developed a new high-resolution X-ray microscope using the X-ray beams of the Advanced Photon Source (APS). The APS is a synchrotron light source that produces high-energy, high-brightness X-ray beams.

In addition to the new X-ray microscope, researchers also created new computer algorithms to compensate for issues encountered at small dimensions. Using this method, researchers achieved a resolution below 10nm. Researchers made various optomechanical breakthroughs with the microscope, leading to fast 3D tomographic acquisitions at sub-10nm spatial resolutions in 85 minutes.

Another issue is drift and deformation. In operation, a sample could move within the beam. Or the X-ray beam could cause a small change in the sample itself. In response, researchers developed a new algorithm, which remove these issues. This in turn results in sharper 3D images. Using the X-ray microscope, researchers captured 2D and 3D images of a sample with 16nm features. They were able to image tiny defects. They also used the system to capture images in an energy storage device.

“We want to be at 10 nanometers or better,” said Michael Wojcik, a physicist in the optics group of Argonne’s X-ray Science Division (XSD). “We developed this for nanotomography because we can obtain 3D information in the 10-nanometer range faster than other methods, but the optics and algorithm are applicable to other X-ray techniques as well.”

Viktor Nikitin, research associate in XSD at Argonne, said: “We will push for eight nanometers and below. We hope this will be a powerful tool for research at smaller and smaller scales.”

X-ray combo
Using a combination of X-ray techniques, the University of Hamburg, DESY, ESRF and the Ludwig Maximilians University have studied the formation of cobalt oxide crystals at the nanometer scale and how they assemble.

Cobalt is used in various fields, including the cathode in lithium-ion batteries for electric vehicles. The industry is using these materials today, but they want to better understand the mechanisms of cobalt oxide. They want to better control the chemical reactions at various length scales.

To solve the problem, researchers used various X-ray metrology techniques to explore the molecular assembly of polyhedrally-shaped cobalt oxide nanocrystals.

Researchers combined HERFD-XANES, PDF, and CD-SAXS to study the emergence of these materials. High energy-resolution fluorescence-detected X-ray absorption near edge structure (HERFD-XANES) is used to analyze electronic and geometric structures of a sample.

Critical-dimension small-angle X-ray scattering (CD-SAXS) uses variable-angle transmission scattering from a small beam size to provide measurements. “Complementary structural information can be obtained from the pair distribution function (PDF) analysis of high-energy in situ X-ray total scattering,” according to researchers in Nature Communications, a technology journal.

For the experiments, researchers used the European Synchrotron Radiation Facility (ESRF) and DESY’s synchrotron radiation source PETRA III. DESY operates one of the world’s brightest storage-ring-based X-ray radiation sources.

Last year, the ESRF opened its rebuilt X-ray source, dubbed ESRF-EBS (Extremely Brilliant Source), the world’s first fourth-generation high-energy synchrotron. ESRF consists of a giant storage ring, a circular tunnel measuring 844 meters in circumference. ESRF-EBS opens the door for new breakthroughs in X-ray science.

Researchers used different X-ray types to study cobalt oxide. ESRF used X-ray spectroscopy to look at the material. “Our technique allows us to follow chemical state changes in complex reactions within a chemical reactor and in real time. Such in situ experiments are always challenging, as we have to reproduce the same experimental conditions as in the laboratory with an extra optical access for the X-ray beam,” said Blanka Detlefs, a researcher in the project.

X-ray scattering was also used. “The superposition (interference) of light waves causes more light to be deflected in certain directions than in others. From this scattering of the X-ray light, we can then calculate how the shape and size of the cobalt oxide nanocrystals develop during their formation process,” explained Cecilia Zito from the University of Hamburg and who is now working at the Sao Paulo State University in Brazil.

China’s X-ray efforts
The Institute of High Energy Physics (IHEP), a Chinese Academy of Sciences research institute, has begun to install the equipment for the High Energy Photon Source (HEPS).

HEPS is the first high-energy synchrotron radiation light source in China and one of brightest fourth-generation synchrotron radiation facilities in the world.

Meanwhile, China’s Platform of Advanced Photon Source (PAPS) has moved into operation. Located opposite of HEPS, PAPS will allow researchers conduct experiments using various X-ray and other systems.



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