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Machine Learning Dramatically Streamlines Search for More Efficient Chemical Reactions

A catalytic reaction may follow thousands of possible paths, and it can take years to identify which one it actually takes so scientists can tweak it and make it more efficient. Now researchers at the Department of Energy's SLAC National Accelerator Laboratory and Stanford University have taken a big step toward cutting through this thicket of possibilities.

Freezing Lithium Batteries May Make Them Safer and Bendable

Columbia Engineering Professor Yuan Yang has developed a new method that could lead to lithium batteries that are safer, have longer battery life, and are bendable, providing new possibilities such as flexible smartphones. His new technique uses ice-templating to control the structure of the solid electrolyte for lithium batteries that are used in portable electronics, electric vehicles, and grid-level energy storage. The study is published online April 24 in Nano Letters.

New Study Reveals the Mystery Behind the Formation of Hollowed Nanoparticles During Metal Oxidation

In a newly published <i>Science</i> paper, Argonne and Temple University researchers reveal new knowledge about the behavior of metal nanoparticles when they undergo oxidation, by integrating X-ray imaging and computer modeling and simulation. This knowledge adds to our understanding of fundamental processes like oxidation and corrosion.

Rare Supernova Discovery Ushers in New Era for Cosmology

With help from a supernova-hunting pipeline based at NERSC, astronomers captured multiple images of a gravitationally lensed Type 1a supernova. This is currently the only one, but if astronomers can find more they may be able to measure Universal expansion within four percent accuracy. Luckily, Berkeley Lab researchers do have a method for finding more.

Making Batteries From Waste Glass Bottles

Researchers at the University of California, Riverside's Bourns College of Engineering have used waste glass bottles and a low-cost chemical process to create nanosilicon anodes for high-performance lithium-ion batteries. The batteries will extend the range of electric vehicles and plug-in hybrid electric vehicles, and provide more power with fewer charges to personal electronics like cell phones and laptops.

Changing the Game

High performance computing researcher Shuaiwen Leon Song asked if hardware called 3D stacked memory could do something it was never designed to do--help render 3D graphics.

A Scientific Advance for Cool Clothing: Temperature-Wise, That Is

Stanford University researchers, with the aid of the Comet supercomputer at the San Diego Supercomputer at UC San Diego, have engineered a low-cost plastic material that could become the basis for clothing that cools the wearer, reducing the need for energy-consuming air conditioning.

Adjusting Solar Panel Angles a Few Times a Year Makes Them More Efficient

With Earth Day approaching, new research from Binghamton University-State of New York could help U.S. residents save more energy, regardless of location, if they adjust the angles of solar panels four to five times a year.

A Real CAM-Do Attitude

A multi-institutional team used resources at the Oak Ridge Leadership Computing Facility to catalog how desert plants photosynthetic processes vary. The study could help scientists engineer drought-resistant crops for food and fuel.

Predictive Power

The Consortium for Advanced Simulation of Light Water Reactors carried out the largest time-dependent simulation of a nuclear reactor ever to support Tennessee Valley Authority and Westinghouse Electric Company during the startup of Watts Bar Unit 2, the first new US nuclear reactor in 20 years. The simulation was carried out primarily on OLCF resources.


3 Small Energy Firms to Collaborate with PNNL

Pacific Northwest National Laboratory is collaborating with three small businesses to address technical challenges concerning hydrogen for fuel cell cars, bio-coal and nanomaterial manufacturing.

ORNL to Collaborate with Five Small Businesses to Advance Energy Tech

Five small companies have been selected to partner with the Department of Energy's Oak Ridge National Laboratory to move technologies in commercial refrigeration systems, water power generation, bioenergy and battery manufacturing closer to the marketplace.

U.S. Department of Energy's INCITE Program Seeks Advanced Computational Research Proposals for 2018

The Department of Energy's INCITE program will be accepting proposals for high-impact, computationally intensive research campaigns in a broad array of science, engineering, and computer science domains.

New Berkeley Lab Project Turns Waste Heat to Electricity

A new Berkeley Lab project seeks to efficiently capture waste heat and convert it to electricity, potentially saving California up to $385 million per year. With a $2-million grant from the California Energy Commission, Berkeley Lab scientists will work with Alphabet Energy to create a cost-effective thermoelectric waste heat recovery system.

New SLAC Theory Institute Aims to Speed Research on Exotic Materials at Light Sources

A new institute at the Department of Energy's SLAC National Accelerator Laboratory is using the power of theory to search for new types of materials that could revolutionize society - by making it possible, for instance, to transmit electricity over power lines with no loss.

Lenvio Inc. Exclusively Licenses ORNL Malware Behavior Detection Technology

Virginia-based Lenvio Inc. has exclusively licensed a cyber security technology from the Department of Energy's Oak Ridge National Laboratory that can quickly detect malicious behavior in software not previously identified as a threat.

Argonne Scientist and Nobel Laureate Alexei Abrikosov Dies at 88

Alexei Abrikosov, an acclaimed physicist at the U.S. Department of Energy's Argonne National Laboratory who received the 2003 Nobel Prize in Physics for his work on superconducting materials, died Wednesday, March 29. He was 88.

Jefferson Lab Accomplishes Critical Milestones Toward Completion of 12 GeV Upgrade

The Continuous Electron Beam Accelerator Facility (CEBAF) at the U.S. Department of Energy's Thomas Jefferson National Accelerator Facility has achieved two major commissioning milestones and is now entering the final stretch of work to conclude its first major upgrade. Recently, the CEBAF accelerator delivered electron beams into two of its experimental halls, Halls B and C, at energies not possible before the upgrade for commissioning of the experimental equipment currently in each hall. Data were recorded in each hall, which were then confirmed to be of sufficient quality to allow for particle identification, a primary indicator of good detector operation.

Valerie Taylor Named Argonne National Laboratory's Mathematics and Computer Science Division Director

Computer scientist Valerie Taylor has been appointed as the next director of the Mathematics and Computer Science division at Argonne, effective July 3, 2017.

Three SLAC Employees Awarded Lab's Highest Honor

At a March 7 ceremony, three employees of the Department of Energy's SLAC National Accelerator Laboratory were awarded the lab's highest honor ­- the SLAC Director's Award.


The Roadmap to Quark Soup

Scientists discover new signposts in the quest to determine how matter from the early universe turned into the world we know today.

Neutrons Play the Lead to Protons in Dance Around "Double-Magic" Nucleus

Electric and magnetic properties of a radioactive atom provide unique insight into the nature of proton and neutron motion.

Ultrafast Imaging Reveals the Electron's New Clothes

Scientists use high-speed electrons to visualize "dress-like" distortions in the atomic lattice. This work reveals the vital role of electron-lattice interactions in manganites. This material could be used in data-storage devices with increased data density and reduced power requirements.

One Small Change Makes Solar Cells More Efficient

For years, scientists have explored using tiny drops of designer materials, called quantum dots, to make better solar cells. Adding small amounts of manganese decreases the ability of quantum dots to absorb light but increases the current produced by an average of 300%.

Electronic "Cyclones" at the Nanoscale

Through highly controlled synthesis, scientists controlled competing atomic forces to let spiral electronic structures form. These polar vortices can serve as a precursor to new phenomena in materials. The materials could be vital for ultra-low energy electronic devices.

In a Flash! A New Way for Making Ceramics

A new process controllably but instantly consolidates ceramic parts, potentially important for manufacturing.

Deciphering Material Properties at the Single-Atom Level

Scientists determine the precise location and identity of all 23,000 atoms in a nanoparticle.

Smallest Transistor Ever

It has long been thought that building nanometer-sized transistors was impossible. Simply put, the physics and atomic structural imperfections couldn't be overcome. However, scientists built fully functional, nanometer-sized transistors.

Creation of Artificial Atoms

For the first time, scientists created a tunable artificial atom in graphene. The results from this research demonstrate a viable, controllable, and reversible technique to confine electrons in graphene.

Developing Tools to Understand Lithium-Ion Battery Instabilities

Scientists develop tools to understand Li-ion battery instabilities, enabling the study of electrodes and solid-electrolyte interphase formation.


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Breakthrough Next-Gen NIF Optics Boost Energy and Limit Damage

Article ID: 672554

Released: 2017-04-06 06:05:57

Source Newsroom: Lawrence Livermore National Laboratory

  • Credit: Photo credit – Jason Laurea/LLNL.

    Marcus Monticelli inspects the anti-reflective coating on a new NIF grating debris shield. The coating restores lost NIF energy and eliminates a source of optics damage.

  • Standard manufacturing techniques produced coated GDS optics with 14-16 percent contrast in diffraction efficiency (left) and were unusable. Improved techniques reduced the contrast to an acceptable 8-12 percent.

LIVERMORE, California – A new anti-reflective coating and a novel chemical process for laser optics, developed by Lawrence Livermore National Laboratory (LLNL) researchers, represents an important breakthrough in its effort to boost the energy of the National Ignition Facility’s (NIF) 192 giant lasers and cut the cost of repairing or replacing damaged optics vital to its operation.

The coating was developed to overcome energy-robbing reflections from the rear surface of the laser facility’s grating debris shields, or GDS. The GDS is the penultimate optic before NIF’s laser beams enter the target chamber, protecting other optics from the target chamber environment and assisting in diagnosis of the energy of NIF’s laser beams.

A patented chemical process, called the Advanced Mitigation Process (AMP), further protects the optics by making their surfaces more damage resistant by removing impurities and absorbing microfractures. These imperfections, when exposed to laser light, create tiny damage craters on the surface, which grow with repeated laser shots and limit the life span of the optic.  Both the AMP process and the coating are required to realize these reductions to the damage rate and the possibility of higher energy on NIF.

These technologies are a result of sustained research and development over the past decade, much of it supported by LLNL’s Laboratory Directed Research and Development (LDRD). This effort involved forming a fundamental understanding of the chemistry and physics involved – including isolating and identifying nanoscale absorbing precursors leading to laser damage, understanding the complex laser matter interaction physics and developing novel chemical processes to mitigate them.

“Maximizing the amount of energy and shots reaching NIF targets is a critical factor in the facility’s efforts to serve the needs of its users and laboratory missions,” said Tayyab Suratwala, program director for Optics and Materials Science and Technology (OMST). “By minimizing the damage rate to NIF’s optics, we can save considerable time and expense involved in recycling or replacing optics that become unusable, and thereby increase the number of shots available to experimenters.”

NIF is the world’s largest and highest-energy laser system, capable of creating the extreme temperatures and pressures necessary for science-based stockpile stewardship and deepening  understanding of the universe. In NIF laser shots, a complex series of optics, including amplifiers, mirrors and wavelength converters, strengthens and guides laser light into the target chamber, where it is focused on miniature targets for inertial confinement fusion and high energy density physics experiments.

The GDS diffracts a small amount of laser light and sends it to a device used to measure its energy, to help researchers balance the laser energy in NIF’s beams as they enter the target chamber. Problematic reflections from this optic ultimately became responsible for much of the damage it experiences, according to Marcus Monticelli, LLNL process engineer lead.

A grating is a diffractive optic that splits light into different wavelengths that travel in certain directions, roughly analogous to the rainbow pattern seen on the back of a compact disc. “These gratings have to be very stable,” Monticelli said. “The way to keep it stable, historically, was to leave it uncoated, because the index of refraction of the coating can change with time. That will affect diffraction efficiency significantly, and that would cause power balancing issues on NIF.”

But leaving a fused silica optic like the GDS uncoated results in a penalty in energy: at the 352-nanometer, or ultraviolet, wavelength of NIF’s lasers, 3.7 percent of the laser energy reflects up the beamline from the optic’s exit surface and must be captured by a beam dump so it won’t damage other optics.  “When you’re talking about 1.8 megajoules on NIF in 3 nanoseconds, that’s a very big chunk of power,” Monticelli said, noting that researchers have sardonically joked that “the world’s largest laser is NIF, and the world’s second largest laser is the reflection off NIF optics.”

Some of this reflected light bounced around in the integrated optics module (IOM) containing the final optics, creating a highly focused beam of light, a focusing “ghost,” that was intense enough to damage the IOM’s stray-light-absorbing glass just above the exit surface of the GDS. “Every time we shot the laser,” said Jeff Bude, science and technology lead. “It was damaging the IOM and spewing debris all over the GDS.”

The debris particles created thousands of potential damage sites on the GDS, many of which, when exposed to NIF’s high-energy laser beams, eventually grew large enough to render the optic useless. “The debris causing damage was limiting the performance of the inherently damage-resistant AMP-treated optic,” Bude said. “Understanding and solving this problem was a result of sustained research and development on the impact of various types of debris on laser damage and from novel experiments on NIF and in offline laser test laboratories.”

Due to this and other causes, as many as 30-40 optics a week had to be removed from service so that damage sites could be locally repaired through a process known as the “NIF Recycle Loop.” The loop is designed to assure that NIF economically operates at maximum energy by limiting the likelihood of damage and acting quickly to mitigate further damage when it does occur.

To solve the reflected-light problems, an LLNL-developed colloidal silica particle coating, made by a sol-gel chemical process, was used on the grating surface of the GDS. These particles were treated with a chemical that modifies the surface, making them more immune to changes in humidity and other environmental factors, and tests showed it was ideal for use as a GDS coating. To accommodate the coatings, the team needed to modify the process for lithographically imprinting the holographic gratings on the exit surface of the GDS optics. Controlled experiments using both standard and coated GDS, combined with other laser improvements such as reducing beam contrast, showed a more than 50-fold reduction in the number of problematic damage sites.

Testing the coated and AMPed GDS began about two years ago. As of March, NIF is about three quarters of the way through replacing uncoated GDS with the new model as the older versions outlive their usefulness. The team predicts that the recycle rate for damaged optics will be cut in half – from 30-40 a week to 10-20 a week – when all the anti-reflective GDS are in place. At the current shot rate, the number of new GDS that will need to be purchased will drop from about 130 a year to about 40, Suratwala said – a significant cost savings.

NIF experiments support the National Nuclear Security Administration’s Stockpile Stewardship Program to ensure the safety, security and reliability of the nation’s nuclear deterrent, while also providing scientists from around the world with unique conditions of heat and pressure for fundamental science studies.

The results of this effort will be published as part of an Optics Express paper later this spring.

Founded in 1952, Lawrence Livermore National Laboratory (www.llnl.gov) provides solutions to our nation’s most important national security challenges through innovative science, engineering and technology. Lawrence Livermore National Laboratory is managed by Lawrence Livermore National Security, LLC for the U.S. Department of Energy's National Nuclear Security Administration.

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