tomography – Page 2 – Lightsources.org

World record: Fastest 3D tomographic images at BESSY II

2018/08/082018/08/09

An HZB team has developed an ingenious precision rotary table at the EDDI beamline at BESSY II and combined it with particularly fast optics.

This enabled them to document the formation of pores in grains of metal during foaming processes at 25 tomographic images per second – a world record.

The quality of materials often depends on the manufacturing process. In casting and welding, for example, the rate at which melts solidify and the resulting microstructure of the alloy is important. With metallic foams as well, it depends on exactly how the foaming process takes place. To understand these processes fully requires fast sensing capability. The fastest 3D tomographic images to date have now been achieved at the BESSY II X-ray source operated by the Helmholtz-Zentrum Berlin.

Dr. Francisco Garcia-Moreno and his team have designed a turntable that rotates ultra-stably about its axis at a constant rotational speed. This really depends on the highest precision: Any tumbling around the rotation axis or even minimal deviations in the rotation speed would prevent the reliable calculation of the 3D tomography. While commercially available solutions costing several hundred thousand euros allow up to 20 tomographic images per second, the Berlin physicists were able to develop a significantly cheaper solution that is even faster. ”My two doctoral students at the Technische Universität Berlin produced the specimen holders themselves on the lathe”, says Garcia-Moreno, who not only enjoys working out solutions to tricky technical problems, but possesses a lot of craftsman skill himself as well. Additional components were produced in the HZB workshop. In addition, Garcia-Moreno and his colleague Dr. Catalina Jimenez had already developed specialized optics for the fast CMOS camera during the preliminary stages of this work that allows even for simultaneous diffraction. This makes it possible to record approximately 2000 projections per second, from which a total of 25 three-dimensional tomographic images can be created.

Image: Experimental setup is composed of a fast-rotation stage, an IR heating lamp (temperature up to 800 °C), a BN crucible transparent to X-rays, a 200-μm thick LuAG:Ce scintillator, a white-beam optical system, and a PCO Dimax CMOS camera. The incident (red) and transmitted (green) X-ray beams as well as the light path from the scintillator to the camera (blue) are shown.
Credit: HZB

3D X-ray tomography scoops up information about ice cream

2018/07/192018/07/24

There’s nothing quite like an ice cream on a hot day, and eating it before it melts too much is part of the fun.

Ice cream is a soft solid, and its appeal is a complex combination of ‘mouthfeel’, taste and appearance, which are all strongly affected by the underlying microstructure. We know that changes in the microstructure of ice cream occur at storage temperatures above -30°C, so they will occur during shipping, and in freezers at the supermarket and at home. In their ongoing quest to create the perfect ice cream, an international team of researchers brought samples to Diamond to investigate the temperature dependence of these microstructural changes, and the underlying physical mechanisms that control microstructural stability.

Research shows how to improve the bond between implants and bone

2018/07/032018/07/05

Research carried out recently at the Canadian Light Source (CLS) in Saskatoon has revealed promising information about how to build a better dental implant, one that integrates more readily with bone to reduce the risk of failure.

“There are millions of dental and orthopedic implants placed every year in North America and a certain number of them always fail, even in healthy people with healthy bone,” said Kathryn Grandfield, assistant professor in the Department of Materials Science and Engineering at McMaster University in Hamilton.

A dental implant restores function after a tooth is lost or removed. It is usually a screw shaped implant that is placed in the jaw bone and acts as the tooth roots, while an artificial tooth is placed on top. The implant portion is the artificial root that holds an artificial tooth in place.

Grandfield led a study that showed altering the surface of a titanium implant improved its connection to the surrounding bone. It is a finding that may well be applicable to other kinds of metal implants, including engineered knees and hips, and even plates used to secure bone fractures.

About three million people in North America receive dental implants annually. While the failure rate is only one to two percent, “one or two percent of three million is a lot,” she said. Orthopedic implants fail up to five per cent of the time within the first 10 years; the expected life of these devices is about 20 to 25 years, she added.

“What we’re trying to discover is why they fail, and why the implants that are successful work. Our goal is to understand the bone-implant interface in order to improve the design of implants.”

Google Maps for the cerebellum

2018/06/282018/07/12

A team of researchers from Göttingen has successfully applied a special variant of X-ray imaging to brain tissue. With the combination of high-resolution measurements at DESY’s X-ray light source PETRA III and data from a laboratory X-ray source, Tim Salditt’s group from the Institute of X-ray Physics at the Georg August University of Göttingen was able to visualize about 1.8 million nerve cells in the cerebellar cortex. The researchers describe the investigations with the so-called phase contrast tomography in the Proceedings of the National Academy of Sciences (PNAS).
The human cerebellum contains about 80 percent of all nerve cells in 10 percent of the brain volume – one cubic millimeter can therefore contain more than one million nerve cells. These process signals that mainly control learned and unconscious movement sequences. However, their exact positions and neighbourhood relationships are largely unknown. “Tomography in the so-called phase contrast mode and subsequent automated image processing enables the cells to be located and displayed in their exact position,” explains Mareike Töpperwien from the Institute of X-ray Physics at the University of Göttingen, lead author of the publication.

Image: Result of the phase contrast X-ray tomography at DESY’s X-ray source PETRA III.
Credit: Töpperwien et al., Universität Göttingen

Dark-field X-ray microscopy provides surprising insight on ferroelectrics

2018/06/252018/07/04

Thanks to the unique capabilities of in-situ dark-field X-ray microscopy, scientists have now been able to see the complex structures hidden deep inside ferroelectric materials. The results, published today in Nature Materials, contradict previous studies in which only the surface was studied. This revolutionary new technique will be the main feature of a new beamline for the new EBS machine currently being built at the ESRF.

“Until now we could only see the surface of the material; dark-field x-ray microscopy is like creating a window to its interior”, explains Hugh Simons, assistant professor at the Technical University of Denmark and corresponding author of the study. “It provides incredible contrast for even the subtlest structures inside these materials, giving us a much clearer picture of how they work”, he adds.

Simons, together with the team of ID06 – the beamline where the technique is being developed – studied the ferroelectric material BaTiO₃, which is used every day in cars, computers and mobile phones. By imaging their internal structure at the same time as they applied an electric field on it, they could see how these internal structures behave and change dynamically.

Image: (extract) Crosssectional dark-field x-ray microscopy maps of the embedded BaTiO₃ grain. (…) the reconstructed strain map reveals the structural relationship between domain clusters. Full picture here.
Credit: H. Simons.

The early bird got to fly: Archaeopteryx was an active flyer

2018/03/122018/03/14

Was Archaeopteryx capable of flying, and if so, how?

The question of whether the Late Jurassic dino-bird Archaeopteryx was an elaborately feathered ground dweller, a glider, or an active flyer has fascinated palaeontologists for decades. Valuable new information obtained with state-of-the-art synchrotron microtomography at the ESRF, the European Synchrotron (Grenoble, France), allowed an international team of scientists to answer this question in Nature Communications. The wing bones of Archaeopteryx were shaped for incidental active flight, but not for the advanced style of flying mastered by today’s birds.

Was Archaeopteryx capable of flying, and if so, how? Although it is common knowledge that modern-day birds descended from extinct dinosaurs, many questions on their early evolution and the development of avian flight remain unanswered. Traditional research methods have thus far been unable to answer the question whether Archaeopteryx flew or not. Using synchrotron microtomography at the ESRF’s beamline ID19 to probe inside Archaeopteryx fossils, an international team of scientists from the ESRF, Palacký University, Czech Republic, CNRS and Sorbonne University, France, Uppsala University, Sweden, and Bürgermeister-Müller-Museum Solnhofen, Germany, shed new light on this earliest of birds.

Image: The Munich specimen of the transitional bird Archaeopteryx. It preserves a partial skull (top left), shoulder girdle and both wings slightly raised up (most left to center left), the ribcage (center), and the pelvic girdle and both legs in a “cycling” posture (right); all connected by the vertebral column from the neck (top left, under the skull) to the tip of the tail (most right). Imprints of its wing feathers are visible radiating from below the shoulder and vague imprints of the tail plumage can be recognised extending from the tip of the tail.
Credits: ESRF/Pascal Goetgheluck

Natalie Larson awarded

2017/11/142017/12/07

She received the Neville B. Smith Student Poster Prize

Natalie Larson, a current ALS doctoral fellow from UC Santa Barbara, won the first prize Neville B. Smith Student Poster Award at the 2017 ALS User Meeting. Larson’s winning poster—”In-situ x-ray computed tomography of defect evolution during polymer impregnation and pyrolysis processing of ceramic matrix composites”—featured the first two big in situ experiments she performed at Beamline 8.3.2.

Larson has been an ALS user since 2014 and became a doctoral fellow in 2016. She’ll continue at the ALS for about another year through a National Science Foundation fellowship that will see her through the end of her PhD. The primary focus of her work is developing high-temperature ceramic matrix composites (CMCs) for more efficient jet engines. Larson works with Beamline Scientists Dula Parkinson and Alastair MacDowell and Project Scientist Harold Barnard on developing experiments for in situ x-ray computed tomography experiments to observe 3D real-time defect formation in CMCs.

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