Secrets of the deadly white-tail virus revealed

The inner workings of a lethal giant freshwater prawn virus have been revealed by an international team of researchers using data gathered at Diamond Light Source. The results reveal a possible new class of virus and presents the prospect of tackling a disease that can devastate prawn farms around the world.

The detailed structure of a virus that can devastate valuable freshwater prawn fisheries has been revealed by an international team using image data collected in the Electron Bio-Imaging Centre (eBIC) based at Diamond Light Source. The researchers produced high-resolution images of virus like particles, VLP’s, composed of virus shell proteins which they compared with lower resolution images of the complete virus purified from prawn larvae. They found strong similarities between the two suggesting that the more detailed VLP images are a good representation of the intact virus. This research, exposing the inner workings of the MrNV, could make it easier to develop ways of combating the economically important disease, but also suggests that it belongs in a new, separate, group of nodaviruses.
The researchers used the rapidly developing technique of cryo-electron microscopy, cryoEM, which has the ability to produce very high-resolution images of frozen virus particles. Images so detailed that the positions of individual atoms could be inferred. Recent breakthroughs in this technique have transformed the study of relatively large biological complexes like viruses allowing researchers to determine their structures comparatively quickly. The data to produce the MrNV structure described here was captured in two days at the eBIC facility.

>Read more on the Diamond Light Source website

Image: 3D model of the MrNV
Credit: Dr David Bhella

Topological matters: toward a new kind of transistor

X-ray experiments at Berkeley Lab provide first demonstration of room temperature switching in ultrathin material that could serve as a ‘topological transistor’

Billions of tiny transistors supply the processing power in modern smartphones, controlling the flow of electrons with rapid on-and-off switching. But continual progress in packing more transistors into smaller devices is pushing toward the physical limits of conventional materials. Common inefficiencies in transistor materials cause energy loss that results in heat buildup and shorter battery life, so researchers are in hot pursuit of alternative materials that allow devices to operate more efficiently at lower power.
Now, an experiment conducted at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) has demonstrated, for the first time, electronic switching in an exotic, ultrathin material that can carry a charge with nearly zero loss at room temperature. Researchers demonstrated this switching when subjecting the material to a low-current electric field.

>Read more on Advanced Light Source (ALS) at LBNL website

Image: James Collins, a researcher at Monash University in Australia, works on an experiment at Beamline 10.0.1, part of Berkeley Lab’s Advanced Light Source.
Credit: Marilyn Chung/Berkeley Lab

Milestone for bERLinPro: photocathodes with high quantum efficiency

A team at the HZB has improved the manufacturing process of photocathodes and can now provide photocathodes with high quantum efficiency for bERLinPro.

Teams from the accelerator physics and the SRF groups at HZB are developing a superconducting linear accelerator featuring energy recovery (Energy Recovery Linac) as part of the bERLinPro project. It accelerates an intense electron beam that can then be used for various applications – such as generating brilliant synchrotron radiation. After use, the electron bunches are directed back to the superconducting linear accelerator, where they release almost all their remaining energy. This energy is then available for accelerating new electron bunches.

Electron source: photocathode

A crucial component of the design is the electron source. Electrons are generated by illuminating a photocathode with a green laser beam. The quantum efficiency, as it is referred to, indicates how many electrons the photocathode material emits when illuminated at a certain laser wavelength and power. Bialkali antimonides exhibit particularly high quantum efficiency in the region of visible light. However, thin films of these materials are highly reactive and therefore very sensitive, so they only work at ultra-high vacuum.

>Read more on the Bessy II at HZB website

Image: Photocathode after its production in the preparatory system.
Credit: J. Kühn/HZB

Tunable ferromagnetism in a 2D material at room temperature

Breakthroughs in next-generation spintronic logic and memory devices could hinge on our ability to control spin behavior in two-dimensional materials—stacks of ultrathin layers held together by relatively weak electrostatic (van der Waals) forces. The reduced dimensionality of these so-called “van der Waals materials” often leads to tunable electronic and magnetic properties, including intrinsic ferromagnetism. However, it remains a challenge to tune this ferromagnetism (e.g. spin orientation, magnetic domain phase, and magnetic long-range order) at ambient temperatures.

In this work, researchers performed a study of Fe3GeTe2, a van der Waals material that consists of Fe3Ge layers alternating with two Te layers. The material’s magnetic properties were characterized using a variety of techniques, including x-ray absorption spectroscopy (XAS) with x-ray magnetic circular dichroism (XMCD) contrast at Beamline 6.3.1 and photoemission electron microscopy (PEEM) at Beamline 11.0.1.

>Read more on the Advanced Light Source (ALS) at LBNL website

Image: PEEM images for unpatterned and patterned Fe3GeTe2 samples at 110 K and 300 K. The unpatterned samples formed stripe domains at 110 K, which disappeared at 300 K. The patterned samples formed out-of-plane stripe domains at 110 K and transitioned to in-plane vortex states at 300 K, demonstrating control over magnetism at room temperature and beyond.

WE45 SSRL Slider

The Stanford Synchrotron Radiation Lightsource (SSRL) is one of the pioneering synchrotron facilities in the world, known for outstanding user support, training future generations and important contributions to science and instrumentation. SSRL is an Office of Science User Facility operated for the U.S. Department of Energy by Stanford University.

W45 FERMI Slider

The program of construction and commissioning through user experiments of the FEL source FERMI, the only FEL user facility in the world currently exploiting external seeding to offer intensity, wavelength and line width stability, achieved all of its intended targets in 2017.

Capturing the strongest X-ray beam on Earth

First images of the European XFEL beam

At European XFEL scientists use intense X-rays to take pictures of the smallest particles imaginable. The European XFEL X-ray beam is a billion times brighter than other traditional X-ray sources, but since X-rays are invisible to the naked eye, it is not usually possible to see the X-ray beam. Working together with a professional photographer, scientists at the largest X-ray laser in the world located in Schenefeld near Hamburg, have now managed to capture an image of the intense European XFEL X-ray beam. The pictures were taken as the X-ray beam entered the experiment area in the FXE instrument hutch at the end of a journey that started in a 3.4km long underground tunnel.

On the images published today, the X-ray beam appears as a thin blue stripe. What we are actually seeing, however, is glowing nitrogen molecules which the X-ray beam has caused to light up as it travels through the air thereby interacting with the molecules.

>Read more on the European XFEL website

Image: The European XFEL beam.
Credit: European XFEL

Improving lithium-ion battery capacity

Toward cost-effective solutions for next-generation consumer electronics, electric vehicles and power grids.

The search for a better lithium-ion battery—one that could keep a cell phone working for days, increase the range of electric cars and maximize energy storage on a grid—is an ongoing quest, but a recent study done by Canadian Light Source (CLS) scientists with the National Research Council of Canada (NRC) showed that the answer can be found in chemistry.
“People have tried everything at an engineering level to improve batteries,” said Dr. Yaser Abu-Lebdeh, a senior research officer at the NRC, “but to improve their capacity, you have to play with the chemistry of the materials.”

>Read more on the Canadian Light Source website

Image: The decomposition of a polyvinylidene fluoride (PVDF) binder in a high energy battery.
Credit: Jigang Zhou