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Science Highlights, January 2018

Awards and Recognition

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Awards and Recognition

Brenda Dingus receives Mexican Physical Society’s 2017 Medal

Brenda Dingus

Brenda Dingus

The Mexican Physical Society’s Division of Particles and Fields has given Brenda Dingus (Neutron Science and Technology, P-23) the 2017 Medal. The award honors her developments for physics in Mexico, particularly her work establishing the High-Altitude Water Cherenkov Gamma-Ray Observatory (HAWC) in the state of Puebla, Mexico and her ongoing work on the HAWC project. The medal is the society’s highest distinction and recognizes notable contributions by Mexican scientists or foreigners to the development of particle and field physics in Mexico.

Dingus, who has more than two decades of experience in gamma-ray astronomy, has been involved in some of the field’s most important discoveries. She has conducted pioneering work in gamma-ray bursts and made contributions to the relatively young field of very high-energy gamma-ray astronomy.

Dingus was the DOE principal investigator and managed the construction of HAWC. She has held two two-year terms as the project’s U.S. spokesperson. From 2010 to 2014 Dingus led the HAWC collaboration team – comprising 140 scientists from 23 United States and Mexican institutions. Her vision, leadership, and management made the Laboratory an internationally recognized leader in observational astrophysics and part of a wider network of land- and satellite-based telescopes probing the universe to answer fundamental questions.

Dingus received a Ph.D. in experimental cosmic-ray physics from the University of Maryland – College Park. Prior to coming to Los Alamos in 2002, she was a tenured professor first at the University of Utah and then at the University of Wisconsin. Dingus has received numerous awards and honors including a Presidential Early Career Award for Scientists and Engineers, a Los Alamos Distinguished Performance Award, and is a Fellow of the American Physical Society and Los Alamos National Laboratory.

The Mexican Physical Society (Sociedad Mexicana de Física, in Spanish) is a non-profit organization founded in 1951 to promote research and teaching in physics, to foster interest in science and especially physics among people in Mexico, and to establish close links with similar organizations within Mexico and abroad. The society has 1,400 members and 13 topical divisions. Technical contact: Brenda Dingus

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Arthur Voter recognized with American Chemical Society Award

Arthur Voter

Arthur Voter

The American Chemical Society (ACS) has awarded Los Alamos National Lab Fellow Arthur Voter (Physics and Chemistry of Materials, T-1) the 2018 ACS Physical Chemistry Division Award in Theoretical Chemistry. The ACS cited him: “For pioneering the development of accelerated molecular dynamics methods and their application to key problems in physical chemistry and materials science.”

As the award recipient, Voter will receive an honorarium and a plaque, and he has been invited to the next Telluride School on Theoretic Chemistry (TSTC) in 2019 as an honored guest. Voter will be presented the award and will be given the opportunity to present a plenary lecture at TSTC. Additionally, Voter will present and be recognized at the annual reception sponsored by the Physical Division and the Journal of Physical Chemistry at the fall ACS meeting in Boston that follows TSTC.

Voter joined the Laboratory in 1983 as a postdoctoral fellow after completing his Ph.D. in chemistry at the California Institute of Technology. He transitioned to a technical staff member in 1985 in the Theoretical (T) Division. Voter is a Fellow of the American Physical Society and Los Alamos National Laboratory. His research focuses on the development and application of atomistic simulation methods for problems in chemistry, physics, and materials science. Voter designs ways to study infrequent events, also known as activated processes. He has contributed to over 130 articles and recently published research in Computational Materials Science and Physical Review Letters.

The American Chemical Society is the world’s largest scientific society, including over 150,000 members in more than 140 countries. The U.S. Congress chartered the ACS in 1876, with a mission to “advance the broader chemistry enterprise and its practitioners for the benefit of Earth and its people.” The society produces over 50 peer-reviewed journals and has published more than 8700 articles by chemistry Nobel Laureates.

Jack Simons, a chemistry professor at the University of Utah, founded the Telluride School on Theoretical Chemistry in 2009. The TSTC is held biennially and includes 30 collaborators selected through a competitive process. The collaborators meet with a handful of senior faculty members as well as the ACS Physical Division Awardee – Arthur Voter in 2019. The one-week intensive program includes daily lectures focusing on electronic structures, statistical mechanics, and chemical dynamics as well as problem solving sessions and outdoor activities enjoying the local area of Telluride, CO. Technical contact: Arthur Voter

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Angel Garcia and Laura Smilowitz honored as Fellows of the AAAS

The American Association for the Advancement of Science (AAAS) has selected Angel E. Garcia (Center for Nonlinear Studies, T-CNLS) and Laura Smilowitz (Physical Chemistry and Applied Spectroscopy, C-PCS) as Fellows. Election as a Fellow of AAAS is an honor bestowed upon Association members by their peers for their scientifically or socially distinguished efforts to advance science or its applications. New Fellows will be presented with an official certificate and a gold and blue (representing science and engineering, respectively) rosette pin on February 17 at the AAAS Fellows Forum during the 2018 AAAS Annual Meeting in Austin, TX.

As part of the AAAS Section on Physics, Angel E. Garcia was elected AAAS Fellow for distinguished contributions to computational and theoretical biological physics involving the structure and stability of biomolecules, especially protein folding, membranes, and amyloid formation.
Angel Garcia

Angel Garcia

Garcia received a Ph.D. in theoretical physics from Cornell University and joined the Laboratory in 1989. He held the position of Group Leader of the Lab’s Theoretical Biology and Biophysics Group from 2001 to 2005. Garcia served as Senior Constellation Professor for Biocomputation and Bioinformatics at Rensselaer Polytechnic Institute from 2005 to 2015 and the Physics Department Head at Rensselaer Polytechnic Institute from 2011 to 2015.

He returned to Los Alamos in 2015 as Leader of the Center for Nonlinear Studies. His research focuses on theoretical and computational studies of the structure, dynamics, and stability of biological molecules. Garcia is a Fellow of the American Physical Society, the Biophysical Society, and the American Chemical Society; and serves as the Associate Editor of Proteins, Structure, Function and Bioinformatics.

Laura Smilowitz

Laura Smilowitz

As part of the AAAS Section on Chemistry, Laura Smilowitz was elected Fellow for advancing our understanding of thermal explosions through development and application of diagnostics to separate and illuminate the complex interacting mechanisms controlling the response.

Smilowitz received a Ph.D. in physics from the University of California – Santa Barbara, and then joined the Lab as a Director’s Postdoctoral Fellow. After serving as a research associate at Brandeis University, Smilowitz returned to Los Alamos as a technical staff member in 1999. She currently leads the Weapons Chemistry team in C-PCS. Smilowitz has received a Laboratory Distinguished Performance Award for developing a new x-ray imaging capability. Her recent work has culminated in the use of penetrating radiographic techniques to study dynamic, spontaneous phenomena, which could transform our understanding of the thermal response of energetic materials. The American Physical Society has elected her to the rank of Fellow.

The American Association for the Advancement of Science (AAAS) is the world’s largest general scientific society and publisher of the journal Science, Science Translational Medicine, Science Signaling, Science Advances, Science Immunology, and Science Robotics. AAAS was founded in 1848 and includes nearly 250 affiliated societies and academies of science, serving 10 million individuals. Science has the largest paid circulation of any peer-reviewed general science journal in the world. The non-profit AAAS is open to all and fulfills its mission to “advance science and serve society” through initiatives in science policy, international programs, science education, public engagement, and more. Technical contacts: Angel Garcia and Laura Smilowitz

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David Fry selected as a Fellow of the American Society for Nondestructive Testing

David Fry

David Fry

The American Society for Nondestructive Testing (ASNT) recognized David Fry (Non-Destructive Testing and Evaluation, AET-6) as a Fellow at ASNT’s Annual Conference in

Nashville, TN on November 1, 2017. The ASNT Fellow Award acknowledges and honors members for outstanding service in the field of nondestructive testing. Recipients must have a history in the nondestructive testing fields of research and development, application, teaching and/or management. At least 15 years of professional nondestructive testing-related experience and at least 10 years of ASNT membership are required. The ASNT selects up to fifteen recognitions each year, provided all nominees have met the established guidelines. There were nine recipients in 2017.

Fry joined the Lab in 1989 after receiving his Master’s degree in nuclear engineering from The Ohio State University. He has worked in nondestructive testing his entire career (five different groups all at the Lab’s TA-8 site). Fry began his career at Los Alamos by assisting Hercules Corporation with a problem with the MX missile. He developed a new x-ray imaging technique that identified the issue and indicated the corrective action. Subsequently, Fry worked on the final eight nuclear tests at the Nevada Test Site before testing ended. He then built and delivered a mobile radiography capability for the Russian Federation’s nuclear weapons accident response program under the Nunn-Lugar Act. Fry has qualified five radiographic processes for the Pit Manufacturing program, including one used at Lawrence Livermore National Laboratory. He participates in the Accident Response Group (ARG) and Disposition Forensics Evaluation and Analysis Team (DFEAT) programs, and has been the Nondestructive Evaluation lead since 1991.

Fry has been involved in the development of radiography standards through ASTM International since 2005 and chairs the Reference Radiological Images subcommittee. He developed the standard for microfocus x-ray focal spot measurement with colleagues from the German Institute for Materials and Testing. Recently, Fry has been upgrading the radiography equipment at the Device Assembly Facility (DAF) at the Nevada National Security Site. He is an expert throughout the NNSA enterprise assisting with work at Pantex, Y-12, and Sandia as well as DoD facilities. Fry has led several CRADAs and Work for Others projects in areas of x-ray detectors, analysis of rock fall protection fences, and airbag development. He has received 15 DOE Defense Programs Awards of Excellence, 2 Laboratory Pollution Prevention Awards, and the ASTM International’s Charles Briggs Award for continuous and outstanding contributions to the work of Committee E07.

The American Society for Nondestructive Testing, Inc. (ASNT) is the world’s largest technical society for nondestructive testing (NDT) professionals. It provides a forum for exchange of NDT technical information, educational materials and programs, and standards and services for the qualification and certification of NDT personnel. ASNT promotes the discipline of NDT as a profession and facilitates NDT research and technology applications. 

ASNT was founded in 1941 (under the name of The American Industrial Radium and X-Ray Society) and currently has a membership of more than 16,000 in over 10 countries. The membership represents a wide cross-section of NDT practitioners working in manufacturing, construction, education, research, consulting, services, and the military. See Technical contact: David Fry

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Christine Anderson-Cook chosen for the American Society of Quality’s Shewhart Medal

Christine Anderson-Cook

Christine Anderson-Cook

The American Society for Quality (ASQ) has selected Christine Anderson-Cook (Statistical Sciences, CCS-6) to receive the 2018 Shewhart Medal. The Medal is given to an individual who has demonstrated the most outstanding technical leadership in the field of modern quality control, especially through the development to its theory, principles, and techniques. Her citation reads: “For exemplary leadership, service, training, research, and applications in solving complex problems through statistical thinking and statistical engineering.”

ASQ is a knowledge-based global community of quality professionals, with nearly 80,000 members dedicated to promoting and advancing quality tools, principles, and practices in their workplaces and communities. Anderson-Cook will receive the Shewhart Medal at ASQ’s World Conference on Quality and Improvement to be held in Seattle, WA. The conference takes place April 30 through May 2, 2018. Anderson-Cook earned a Ph.D. in statistics at the University of Waterloo in Canada. Before joining the Laboratory in 2004, she was a faculty member at Virginia Tech for eight years. Her research includes response surface methodology, design of experiments, reliability, multiple criterion optimization, and graphical methods. She has led projects in complex system reliability, non-proliferation, malware detection and statistical design of experiments.

Anderson-Cook has authored more than 180 peer-reviewed papers in statistics and quality peer-reviewed journals and has been a long-time contributor to the Quality Progress Statistics Roundtable column. She has co-edited a compilation book of columns called Statistics Roundtables: Insights and Best Practices. The 4th edition of her book Response Surface Methodology with Raymond Myers and Douglas Montgomery was published in 2016.

She serves on the editorial boards of Technometrics, Quality Engineering, and Quality and Reliability Engineering International. Anderson-Cook is a Fellow of the American Statistical Association and the American Society for Quality. She has won the ASQ Statistics Division’s William G. Hunter Award, NNSA Defense Programs Award of Excellence, 26th Annual Governor’s Award for Outstanding New Mexico Women, the Laboratory Student Distinguished Mentor Award, and the Laboratory Postdoc Distinguished Mentor Award. Technical contact: Christine Anderson-Cook

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E. Flynn, H. Mukundan, N. Sinitsyn, B. Albright, and T. Light win Laboratory Fellows Prizes

Five Los Alamos National Laboratory scientists have been awarded the Laboratory’s prestigious Fellows Prize in the areas of science or engineering research and leadership. Eric Flynn, Harshini Mukundan, and Nikolai Sinitsyn received the Fellows’ Prize for Outstanding Research; and Brian Albright and Tess Light received the Fellows Prize for Outstanding Leadership. 

The Fellows Outstanding Research Prize for science or engineering commends individuals for outstanding research performed at the Laboratory, published or patented within the last 10 years, that has had a significant impact on its discipline and/or Laboratory mission.

Eric Flynn

Eric Flynn

Eric Flynn (Space and Remote Sensing, ISR-2) invented imaging/high-frequency acoustic wavenumber spectroscopy for structural health assessment. This method measures surface and subsurface defects 30 times faster than current technology. This system could significantly advance the way that nondestructive testing is performed on a wide variety of aerospace, civil and mechanical infrastructures. He also wrote the innovative software analysis for this tool.

Flynn first came to the Laboratory for the Engineering Institute’s Dynamics Summer School in 2005, and he returned the following summer as a Lab graduate research assistant. He conducted his doctoral dissertation research as a NSF Graduate Research Fellow in structural engineering at the University of California – San Diego and the Laboratory’s Engineering Institute. After earning a Ph.D., Flynn joined the Laboratory as a Director’s Funded postdoc in 2011. The Lab converted him to a R&D Engineer in 2013.

Flynn’s research focuses on nondestructive testing, signal processing, ultrasonics, applied statistics, optimization, and structural dynamics. He has received a Laboratory Early Career Research Grant (LDRD) for a novel hand-carried laser-ultrasound inspection system and a R&D 100 Award as the principal investigator for the Acoustic Wavenumber Spectrometer.

Flynn was a program developer for the Judicial Science School for New Mexico Judges. He has served as an organizer, mentor, and instructor for the Los Alamos Dynamics Summer Schools; and a guest lecturer for a University of California – San Diego course on Structural Health Monitoring. Flynn has received the Achenbach Medal from the International Workshop on Structural Health Monitoring. Technical contact: Eric Flynn

Harshini Mukundan

Harshini Mukundan

Harshini Mukundan (Physical Chemistry and Applied Spectroscopy, C-PCS) made critical breakthroughs in optical detection techniques of diseases such as tuberculosis, allowing rapid detection in the field, and discovered an entirely new class of diagnostic molecules that led to chemical recognition of various biomarkers. She has numerous awards and patents, and her work is involved in diverse applications including E. coli, breast cancer, traumatic brain injury, and biosurveillance.

Mukundan received a Ph.D. in biomedical sciences from the University of New Mexico and joined Los Alamos as a postdoc in Chemistry Division in 2006, where she had a NIH Postdoctoral fellowship to study tuberculosis and develop methods for its effective diagnosis. The Lab converted her to staff in 2009.

Mukundan has received a Principal Investigator Excellence Award from the New Mexico Small Business Assistance program (NMSBA) for assisting several New Mexico small businesses on two separate projects: bovine tuberculosis detection and better diagnostics for traumatic brain injury. She has been honored with the New Mexico Technology Council’s 8th Annual Women in Technology Award in 2016. Technical contact: Harshini Mukundan

Nikolai Sinitsyn

Nikolai Sinitsyn

Nikolai Sinitsyn (Physics of Condensed Matter and Complex Systems, T-4) works on a wide range of problems including the smart electrical grid, biochemical reactions, and spin noise spectroscopy. He has authored more than 100 peer-reviewed papers with more than 3,700 citations and made a major discovery that illustrates fundamental limitations in quantum computing.

Sinitsyn received a Ph.D. in theoretical physics from Texas A&M University. He joined the Lab as a postdoc in Information Sciences (CCS-3) in 2006. Sinitsyn received a Director's Postdoc Fellowship from 2007-2008 and became a staff member in T-4 in 2010.

Sinitsyn explored experimental data on fluctuations in semiconductor quantum dot spin qubits, which had been previously obtained by Scott Crooker’s team in the National High Magnetic Field Lab (Condensed Matter and Magnet Science, MPA-CMMS) at Los Alamos. Sinitsyn proposed a hypothesis that qubit decoherence is driven by fast nuclear spin fluctuations that are driven, in turn, by electric fields of strains inside materials and nanostructures that confine the qubits. This interaction is commonly known as quadrupole coupling. Its major role in solid state decoherence came as a surprise. Together with postdoc Fuxiang Li (CNLS/T-4), Sinitsyn developed a quantitative theory of decoherence induced by quadrupole interactions. This theory has led to several nontrivial predictions that different experimental groups have observed. The strongest proof of this theory was the observation of a secondary oscillation of a qubit relaxation curve, which A. Bechtold et al. reported in Nature Physics 11, 1005 (2015). Results of this study have ramifications for materials and quantum information research. The results suggest a strategy to suppress decoherence of a quantum dot qubit by orders of magnitude by introducing specific mechanical stresses. Technical contact: Nikolai Sinitsyn

The Outstanding Leadership Prize commends individuals for outstanding scientific and engineering leadership at the Laboratory and recognizes the value of such leadership that stimulates the interest of talented young staff members in the development of new technology.

Brian Albright

Brian Albright

Brian Albright (Primary Physics and Design, XTD-PRI) led a team to make substantial progress in understanding the physics of nuclear weapons, which required going back to basics and rethinking the accepted paradigm. He developed metrics for weapons measurements, which point to the direction of future subcritical experiments.

Albright first came to Los Alamos to participate in the Laboratory’s Summer School in Atomic, Molecular and Optical Physics in 1992. He received a Ph.D. in physics from the University of California – Los Angeles (UCLA). After a short lectureship and postdoc appointment at UCLA, he joined the Lab in 1999 in the Plasma Physics Group (X-1). The Laboratory converted him to technical staff in 2001 in X-1. He is as a 2005 TITANS graduate.

Albright led a code team that was a runner-up for the 2008 Gordon Bell Prize (an international award to recognize achievement in high performance computing) and was among of group of Lab staff who were named in the U.S. Congressional Record in 2008 for their work on the Roadrunner Supercomputer.

Albright has won numerous awards, including a Laboratory Distinguished Performance Award and three DOE Defense Programs Awards of Excellence. He has authored more than 200 publications with more than 4,700 citations. Albright is a Senior Member of the Institute of Electrical and Electronics Engineers (IEEE). Technical contact: Brian Albright

Tess Light

Tess Light

Tess Light (Space and Remote Sensing, ISR-2) is the chief scientist for the Lab’s Space Nuclear Detonation Detection program, leading strategic and tactical planning. She serves as the Electromagnetic Pulse (EMP) phenomenology chief scientist and is recognized as a national authority for EMP nuclear detonation signatures.

Light has codified the Laboratory’s integrity of analysis and interpretation of EMP signatures and established Los Alamos leadership within the U.S. Nuclear Detonation Detection System, making the Laboratory the EMP center of excellence for the system.

Light received a Ph.D. in astrophysics from the University of Minnesota. She joined the Lab as a Director’s Postdoctoral Fellow in the Nonproliferation & International Security (NIS) Division on the FORTE Satellite project in 1999 and became a staff member in 2001. She has received two Individual Los Alamos Achievement Awards, two Team Los Alamos Achievement Awards, a Large Team Distinguished Performance Award, a Los Alamos Director’s Achievement Award, and a Fulbright Fellowship to the Australia Telescope National Facility. Technical contact: Tess Light

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Discovery of a new soil fungus provides insight into the symbiotic relationship with plants

Cheryl Kuske with Bifiguratus adelaidae.

Cheryl Kuske with Bifiguratus adelaidae.

Bifiguratus adelaidae.

Bifiguratus adelaidae.

It is not unusual to find an unknown fungal specimen because the majority of fungi have yet to be discovered and cultured. An estimated 5.1 million different species of fungi exist in the world, yet only approximately 100,000 have been formally characterized. However, with each newly completed organism’s genomic sequence comes the opportunity to compare unknown sequences to known ones, enabling the characterization of new organisms.

In the journal Mycologia, Cheryl Kuske and postdoc Cedar Hesse (Bioenergy and Biome Sciences, B-11), and a team from Western Illinois University and other institutions, characterized a new fungus that they named Bifiguratus adelaidae. The researchers have determined the fungus’s relation in the fungal tree of life. The fungus’s exact placement among the taxonomic order was unknown until now. This fungus, found in North Carolina soil, proved to be of particular importance because it has helped researchers better understand the symbiotic relationship that fungi may have with plants. As noted in the journal’s editorial, “This placement is particularly exciting because of the increased understanding of the mycorrhizal role (ability to form symbiotic, nutrient-transfer relationships) for this part of the phylogeny and the fact that very little is known about the species diversity and distribution in this part of the tree. Bifiguratus adelaidae may have a symbiotic function in roots, having been detected in orchid and chestnut roots, but it is also well-documented in soils from north temperate zones.”

Bifiguratus adelaidae, which they named in honor of the world-recognized tropical biologist Adelaida Chaverri Polini, represents a major component of the observed fungal population in a pine forest. The fungus is interesting to the scientists due to its positive response to elevated carbon dioxide (CO2) and nitrogen amendment treatments that mimic future environmental conditions. However, although this fungus had been detected prior to this characterization, no one had been successful culturing it. Globally, mycologists have included this fungus as one of the “fifty most wanted fungal genomes”.

The team characterized the fungus by comparing its 18S and 28S regions of ribosomal RNA (rRNA) to the similar sequences found in the National Center for Biotechnology Information databases. The researchers compared the strains and found them to be similar in morphology and molecular characters. This collection of data suggested that the fungus Bifiguratus adelaidae should be placed as an early diverging lineage in the Mucoromycotina subdivision of fungi. Detection of bacteria on the fungus supported the idea that many fungi in this subdivision associate with bacteria as well as plant roots. Together these organisms create a healthy soil environment, something scientists hope to thoroughly understand by studying them. Description of this fungus exemplifies the potential to use environmental sequencing to guide taxonomic discovery. Its description and characterization represent a step towards bridging the gap between fungal taxonomy and molecular ecology.

Reference: “Bifiguratus adelaidae, gen. et sp. nov., a New Member of Mucoromycotina in Endophytic and Soil-Dwelling Habitats,” Mycologia 109, 363 (2017); ( Authors: Terry J. Torres-Cruz, Terri L. Billingsley Tobias, Maryam Almatruk, and Andrea Porras-Alfaro (Western Illinois University); Cedar N. Hesse and Cheryl R. Kuske (Bioenergy and Biome Sciences, B-11); Alessandro Desirò, Gian Maria Niccolò Benucci, and Gregory Bonito (Michigan State University); Jason E. Stajich (University of California – Riverside); Christopher Dunlap (USDA); and A. Elizabeth Arnold (University of Arizona).

A Science Focus Area grant from the DOE Office of Science (Office of Biological and Environmental Research) funded the Los Alamos portion of the research, with Los Alamos as the team leader for this activity. The work supports the Lab’s Global Security and Energy Security mission areas and the Science of Signatures science pillar. The Laboratory conducts a wide range of biological research efforts as part of its national security science mission, including research in phylogenetic analysis to determine safe versus dangerous pathogens and to identify disease transmission pathways. Technical contact: Cheryl Kuske

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Capability Enhancement

Obsolete instrument removal makes way for dynamic plutonium experiments

Stages of the HRS removal. (Top): Work begins on disassembling the HRS, the multi-story blue structure in the center of the pRad dome. (Center): One of the last steps in the decommissioning process was disassembling a 135-ton white magnet using a red gantry with a 700-ton capacity. (Bottom): The pRad dome painted and ready.

Stages of the HRS removal. (Top): Work begins on disassembling the HRS, the multi-story blue structure in the center of the pRad dome. (Center): One of the last steps in the decommissioning process was disassembling a 135-ton white magnet using a red gantry with a 700-ton capacity. (Bottom): The pRad dome painted and ready.

A NNSA investment in the Laboratory’s Proton Radiography (pRad) capability has led to the removal of a custom-built, high-resolution spectrometer (HRS) installed in the 1970s. The HRS was designed to explore issues of single and collective nuclear excitation states using both polarized and unpolarized proton beams and targets at what was then known as the Los Alamos Meson Physics Facility. This successful program ended in 1995, when the meson physics facility transitioned to neutron science.

The reconfiguration is part of the effort to restart dynamic plutonium (Pu) experiments at the pRad facility, which uses 800-MeV protons provided by the Los Alamos Neutron Science Center accelerator to diagnose dynamic experiments in support of weapons science and stockpile stewardship programs. Removal of the HRS was a pre-requisite for conducting dynamic Pu experiments in the pRad facility. 

The penetrating power of high-energy protons makes them an excellent probe of a wide range of materials under extreme pressures, strains, and strain rates. The ability to produce multiple proton pulses in an accelerator coupled with multiple optical viewing systems results in 31-frame movies of a dynamic event, with frames separated by 200 nanoseconds.

The re-establishment of the “Pu@pRad” capability will provide an innovative, agile, and flexible platform that complements Nevada National Security Site-integrated large-scale experiments with tomographic imaging and small scale dynamic response studies on plutonium systems with spatial resolutions ranging from 28-100 microns.

The remodel will also enable beamline upgrades such as additional imaging axes, and possibly a more complex combination of electromagnets to further reduce the blur caused by the variation in energy of the protons. A reduced blur would enable sharper images with better spatial resolution while maintaining the field of view of the electromagnet lenses.

Removing the HRS, which weighed about 600 tons, was a multi-faceted project. The extensive deactivation and decommissioning (D&D) process began in September 2016 with competitive bidding by equipment removal companies. The project was awarded to Northwest Demolition and Dismantling, which partnered with Mammoet Inc. D&D started in March 2017, and took about three months to complete, complicated by the radiation-controlled location and the need to disassemble and reassemble the beamline without affecting the upcoming accelerator run cycle. Workers from Mammoet and Northwest Demolition collaborated with Lab staff to disassemble the beam line, dismantle and remove the machinery, and reassemble the beamline in advance of the run cycle.

The core Los Alamos deactivating and decommissioning team included John Ainsworth and Eric Ulibarri (Construction Management, MOF-CM), Michael C. Gonzales (Construction, Projects and Crafts Support, DESHS-CPCS), Julie Maze (ASM Project Procurement, ASM-PROJPR), Effiok Etuk (LANSCE Facility Operations, ES-LFO), and Kyle Deines (Engineering Project Delivery, ES-EPD). Physics Division spearheaded the planning and coordination of the removal effort, led by Frans Trouw (Neutron Science and Technology, P-23), Walter Sondheim and Jason Medina (Subatomic Physics, P-25), and Steven Green (former P-25, now retired). Other Lab workers from electrical safety, waste management, radiological safety, rigging and lifting groups made important contributions. The depth of technical expertise among the Los Alamos crafts enabled a successful outcome for the project.

The HRS’s removal supported one of the core goals of the directorate’s Environmental Action Plan to dispose and clean up legacy equipment. The action plan is part of the Environmental Management System, which helps Los Alamos protect the environment and improve performance.

NNSA funded the work, which supports the Lab’s Nuclear Deterrence mission area and the Materials for the Future and Nuclear and Particle Futures science pillar by enabling dynamic proton radiography studies of materials. Technical contact: Frans Trouw

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X-ray diagnostics of thermal explosions highlighted in Nature and Applied Physics Letters

Researchers are using a table top X-ray radiography technique developed by Chemistry Division staff to study sub-sonic burning of explosives. The team can observe internal convective and conductive burn front propagation and solid consumption subsequent to thermal ignition for several different plastic bonded explosives. This research enables the direct observation and measurement of the rates of energy release during a thermal explosion. The journal Applied Physics Letters published the work, and the journal Nature highlighted it.

The rate of chemical energy release in a thermal explosion has been the topic of considerable research for many years. Super-sonic detonation can be fairly well modelled. However, the response of these materials subsequent to heating when encased and under confinement, resulting in thermal ignition and initial sub-sonic combustion propagation, is relatively poorly understood. The researchers aim to use the data generated by the new technique to understand the combustion rate in explosions.

The publication describes a series of experiments with the laboratory scale dynamic x-ray radiographic system. Researchers imaged the evolution of internal solid density as a function of thermal decomposition and material transport due to heating prior to ignition and propagation post-ignition. A post-ignition application of this radiography imaged the evolution of material density due to the conversion of solid to gas during internal combustion.

When explosives such as HMX or TATB are heated to temperatures above their critical temperature, they begin undergoing exothermic chemistry leading to ignition. Ignition is the transition from thermal decomposition in the solid to conductive and convective combustion as the dominant mechanism of energy release. It divides the regimes of heating in place and burn front propagation. The researchers used fiber optics close to the ignition location to observe ignition. The team suggests that the full mechanism likely involves the ignition of conductive burning of the solid near the initial ignition location, possibly followed by convective propagation of surface ignition through the gas phase, igniting solid consumption by conductive regression from the local surface. Ignition is followed promptly by the propagation of burning, as imaged by x-ray radiography.

A schematic of the assembled experiment.

A schematic of the assembled experiment. Two half cylinders are combined to form a 2:1 aspect ratio cylinder encased in aluminum. The arrows depict imaging axes both along the cylinder axis and side on to the cylinder. Other experimental configurations include a continuous cylindrical case, similar to this schematic, but assembled without a midplane.

In the experiments, six-gram cylinders of energetic material, ½” diameter by 1” long, were encased in an aluminum sleeve and heated radially from outside the aluminum. The technique for dynamic x-ray radiography of the post-ignition combustion uses either a modified medical x-ray source operating at 90 kVp (peak kilovoltage) with a 2-millisecond pulse or a continuous source also operating at 90 kVp. The x-ray transmission was converted to a light image using A thallium doped structured cesium iodide scintillator imaged by a high-speed video camera converted the x-ray transmission to a light image.  

The Figure shows internal combustion of PBX 9502 (95% TATB and 5% Kel-f) subsequent to thermal ignition. Frames are shown every 3 seconds during a 30 s consumption by laminar conductive burning. The initial frame is shown at top left, proceeding to the right and then from left to right in the bottom row. Ignition is shown as a very fast vertical crack and expanding spherical volume in the second frame in the Figure. The nine frames after time = 0 are shown at the same image contrast. Beginning in the third frame, a front propagates from the ignition volume to either end of the case as a front ahead of which the transmission is unchanged and behind which a nearly constant region of high transmission remains. The data indicate a classic, laminar conductive burn in this material under these conditions.
Normalized X-ray images of conductive burning in PBX 9502. Ten frames taken from a x-ray movie illustrating the initial ignition volume and the emanation of a conductive burn front in both directions along the cylinder axis.

Normalized X-ray images of conductive burning in PBX 9502. Ten frames taken from a x-ray movie illustrating the initial ignition volume and the emanation of a conductive burn front in both directions along the cylinder axis.

The team discovered that heat conduction drove the burning of the TATB-containing explosive. However, the studies of HMX indicated that its burning was spurred by a combination of heat conduction and the movement of hot gas, causing faster burning. The researchers suggest that the information from this technique could be used to manipulate the combustion rate in explosions.

Reference: “Internal Sub-Sonic Burning during an Explosion Viewed Via Dynamic X-ray Radiography,” Applied Physics Letters 111, 184103 (2017);

Authors: L. Smilowitz, B. F. Henson, D. Oschwald, N. Suvorova, and D. Remelius (Physical Chemistry and Applied Spectroscopy, C-PCS).

Nature highlight: “X-Rays Reveal the Anatomy of an Explosion,”

The NNSA Science Campaign and Surety Programs and the Joint Munitions Program administered jointly by the Department of Energy and Department of Defense funded the work. The research supports the Lab’s Nuclear Deterrence mission area and the Materials for the Future and Science of Signatures science pillars through the ability to observe and measure rates of energy release during a thermal explosion. Technical contact: Laura Smilowitz

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Earth and Environmental Sciences

SimCCS: An open-source tool for optimizing energy infrastructure developed

Carbon dioxide (CO2) capture and storage (CCS) is a key technology in all climate change mitigation plans that limit global temperatures below 2 °C of warming. To have a meaningful impact, CCS infrastructure would be deployed on a large scale, requiring massive economic investment. At the regional scale, this would involve capturing CO2 from dozens of industrial sources (such as power plants), constructing thousands of kilometres of dedicated CO2 pipelines, and injecting and storing CO2 in geologic reservoirs (such as deep saline aquifers and depleted oil fields). Deploying infrastructure on this scale requires careful and comprehensive planning.

Los Alamos researchers have developed an infrastructure optimization tool that allows the CCS research and commercial communities to design efficient CCS infrastructure networks. SimCCS ( integrates capture, storage, and network engineering with economic analysis to drive CCS infrastructure deployment decisions. The open-source nature of SimCCS enables collaborative, community-driven capability development on a common extensible platform.

SimCCS is an application written in Java that consists of a graphical user interface (GUI) to drive data management, pipeline network generation, and optimization model formulation, solution, and display. The optimization engine that drives infrastructure designs is a mixed integer-linear program that minimizes the aggregate of capture, storage, and transportation costs, while abiding by various networking and capacity constraints. SimCCS includes the capability to integrate with remote high-performance computing resources to solve the optimization problems.
SimCCS graphical user interface

SimCCS graphical user interface displaying an optimal infrastructure design for a southeast United States case study with a target capture amount of 110 Mt CO2/yr over a 30-year project life. A network of dedicated CO2 pipelines (green arcs) connect coal- fired power plants (red circles) and storage reservoirs (blue circles).

CCS infrastructure design requirements motivated the SimCCS work. However, many other infrastructure projects – such as oil, gas, electricity, cyber infrastructure, and communication networks – share the same requirements for simultaneously optimizing networks and resources. Therefore, SimCCS could address energy security solutions and cyberinfrastructure within the Integrating Information, Science and Technology for Prediction science pillar.

Richard Middleton (Computational Earth Science, EES-16, lead developer) and Sean Yaw (EES-16) guided the work. DOE Fossil Energy projects including the US-China Advanced Coal Technology Consortium (under management of West Virginia University), the DOE’s National Energy Technology Laboratory through the Integrated Mid-Continent Stacked Carbon Storage Hub CarbonSAFE, the Early CO2 Storage Complex in Kemper Country CarbonSAFE, and the Rocky Mountain CarbonSAFE projects have funded the SimCCS development. The work supports the Lab’s Energy Security mission area and Integrating Information, Science and Technology for Prediction science pillar through development of the infrastructure optimization tool. Technical contact: Richard Middleton

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Educational Outreach

Lab presents Cyber Fire Forensic Incident and Response Training


Cyber Fire began in 2009 as a joint effort between Sandia National Laboratories and Los Alamos National Laboratory to foster cross-site collaboration on cyber security incident response. Los Alamos picked up the banner in 2010 and the Cyber Fire team, consisting of cyber professionals from both line and program, has continued to refine and grow the effort over the past seven years.

The event delivers expert forensic cybersecurity training using project-based content. Cyber Fire Foundry’s mission is to train all levels of cyber analysts, from entry-level to advanced, in forensic incident response techniques. Graduates of the Cyber Fire Foundry are prepared to investigate forensic evidence of malware intrusion and exfiltration, efficiently coordinate with other incident responders, effectively communicate findings, and have an understanding of forensic incident response concepts that transcends any specific tool. Lawrence Livermore National Laboratory and Idaho National Laboratory have also participated as top collaborators on Cyber Fire by providing subject matter experts from within DOE for instruction of classes and preparation of puzzles. A long track record of collaboration across many of the DOE National Laboratories has built a solid foundation for strong curriculum and content development.

Chris Pavan (Advanced Research in Cyber Systems, A-4) gives a lecture as part of the Host Forensics class.

Chris Pavan (Advanced Research in Cyber Systems, A-4) gives a lecture as part of the Host Forensics class.

The Cyber Fire 11 Foundry Event was held in San Diego, CA in November 2017. It was the largest attended event to date with close to 200 attendees. Organizations that sent representatives include the U.S. Department of Energy, U.S. Department of Defense, National Institutes of Health, U.S. Department of the Treasury, University of Pennsylvania, U.S. Department of Justice and Lockheed Martin.

The Cyber Fire 11 event consisted of 2 days of intensive, hands-on training, followed by a 2-day exercise designed to reinforce the training and introduce new concepts. The exercise included puzzles, classes and simulations, as well as instruction in forensic analysis, JavaScript deobfuscation, network archaeology, malware reverse engineering, sequence analysis, binary file reverse engineering, Snort® mastery, Splunk® mastery and more. Veteran analysts created the curriculum. During the event the Cyber Fire team enhanced the training significantly by fine-tuning the class material, training the next generation of track teachers, branding and promoting the event, and laying the foundation for future improvements.

A significant milestone was reached when Cyber Fire’s cloud-based infrastructure was launched for the first time. No downtime occurred and participants connected readily. Having the server on the public Internet has also generated significant cost and time savings by reducing the physical size of shipping materials for the Cyber Fire event from two 500-pound palettes shipped by ground down to four hand-carried suitcases. As a result, resources can now be better invested in materials which will directly impact attendees and the Cyber Fire Foundry at large. The team used this inaugural event as a pilot project for how cloud services could be utilized within the Lab.

Los Alamos has run Cyber Fire for almost a decade and has trained thousands of cyber analysts from across the federal government, academia, and industry. The cyber analyst team is comprised of experts from Los Alamos, DOE, Idaho National Laboratory, and Lawrence Livermore National Laboratory. Los Alamos benefits directly from the Cyber Fire training suite because it highlights h the Lab’s cybersecurity incident response team and its decades of experience solving computer intrusions. The Laboratory has hired a dozen or so analysts who have attended Cyber Fire.

Los Alamos Cyber Fire Team participants included: Kelcey Tietjen and David Seigel (Office of the Chief Information Officer, OCIO), Chris Pavan, Daniel Byrne, Rachel Atencio, Gillian Hsieh-Ratliff, Chris Rawlings, Joe Taylor, Neale Pickett, Aaron Pope, Jill Jackson, Shannon Steinfadt, Fiona Thomas, and James Wernicke (Advanced Research in Cyber Systems, A-4).

The next Cyber Fire Team event will be held in San Antonio, TX in May followed by another event in San Diego this fall. Attendance is expected to exceed 200 representatives from DOE and other critical infrastructure employees. The team will run four Cyber Fire Simulations where the cyber analysts work with real data from a historical incident to gain experience. Additionally, they will run Cyber Fire Puzzles events at universities as part of a recruitment campaign and the Cyber Fire Summer School for 9 Los Alamos interns where they will work with Cyber Fire class material, analyze incident data, and prepare a detailed report. This activity will enhance future Cyber Fire events and provides a pipeline for cyber talent across the Lab.

The Cyber Fire team aims to increase outreach efforts to engage and educate women and other under-represented minorities. The team is also researching the ability to offer CPE credits for attendees and develop metrics to show the Return on Investment for the sponsors. As the information age rapidly evolves, and new cyber challenges emerge, the Cyber Fire team continues to investigate, coordinate, and better understand forensic incident response with the ultimate goal of transcending specific tools and security measures.

The DOE, Office of the Chief Information Officer currently funds the Cyber Fire Training Suite. NNSA originally funded Cyber Fire (formerly named Tracer Fire). Other organizations have contributed to funding over the years. This work supports the Laboratory’s Global Security mission area and the Integrating Information, Science and Technology for Prediction pillar through the development of forensic incident response techniques. Technical contact: Neale Pickett

Consortium aims to strengthen and diversify the country’s science workforce

A Los Alamos National Laboratory-led effort to diversify the scientific workforce at national laboratories is creating an ever-increasing pipeline of minority students passionate about materials and energy research. The Consortium for Materials and Energy Security (CMaES) is an association of Los Alamos and Lawrence Livermore national laboratories and eight minority-focused colleges and universities providing students with a range of scientific research experiences. Laboratory researchers have mentored 60 students since the founding of CMaES. Many students have later attended graduate school, and some are now working full-time at Los Alamos, making essential contributions to the Lab’s national security science mission.

“To find the best STEM [science, technology, engineering, and math] researchers for the next generation, we need to look everywhere,” said Los Alamos fuel cell researcher Tommy Rockward (Materials Synthesis and Integrated Devices, MPA-11), who originally proposed the project to the NNSA to provide additional talent pools and help diversity efforts in laboratory settings. “CMaES and other programs have allowed more students from underrepresented schools to experience national labs. The consortium is becoming a hub for Lab scientists and staff to find talent.”

For example, 38% of the African-American students who joined Los Alamos over the last several years originally participated in CMaES, which is part of the Lab’s African American Partnership Program.

Recent CMaES students

Recent CMaES students gather in a fuel cell lab at Los Alamos National Laboratory. Standing, from left: Andre Spears (graduate student, MPA-11), mentor Joseph Dumont (Chemical Diagnostics and Engineering, C-CDE), Raluchukwu Onwubuya (post baccalaureate student, formerly with MPA-11) Ling Lin (visiting student from University of Science and Technology of China), Oscar McClain (post baccalaureate student, formerly with MPA-11), and mentor Ulises Martinez (MPA-11). Seated, from left: Jonalyn Fair and Courtland Brown (both post baccalaureate students, formerly with MPA-11).

CMaES gives students hands-on experience in performing scientific research, interpreting data, and writing and presenting reports. These activities prepare them with the necessary skills for a future in science at a national laboratory. Part of its success is due to the program’s flexibility in providing students the opportunity to execute research projects on similar equipment while attending class or working at a national laboratory.

NNSA and Los Alamos National Laboratory’s Director’s Office initially funded the effort. As the program flourished it has gained support from the DOE’s Fuel Cell Technology office. Lawrence Livermore National Laboratory joined CMaES in 2013, giving students a second laboratory setting in which to learn skills and explore career possibilities. 

Students, who are recruited from minority-focused institutes, can get involved via three-day “short courses” in a specific subject, summer internships, and year-long stints. The CMaES Bridge Program places students in one-year appointments at Los Alamos or Livermore. During that time, they are required to apply to graduate school and start research that typically extends into thesis work. Another program, the Los Alamos Dynamics Summer School, has supported CMaES students by pairing them with multidisciplinary Los Alamos researchers for nine-week materials projects spanning electrical, mechanical, structural and cyber-physical systems. Students gain professional experience by presenting their results at an international conference. 

“I really appreciate the opportunity and the exposure I’ve gotten through the Lab,” stated Nia Parker, a post-baccalaureate CMaES student in MPA-11 who plans to enroll in a doctoral program in organic chemistry. “The more knowledgeable I am about the world and the science community, the better.” In MPA-11, Parker is studying disorder and transport in irradiated pyrochlore thin films.

“Deciding to come to Los Alamos was one of the greatest decisions I could have made. I have always known I wanted to attend graduate school; being at LANL has provided me with more ways to achieve that goal,” said Shaylynn Crum (Chemical Diagnostics and Engineering, C-CDE), who joined CMaES as a summer student and is now a post-baccalaureate developing an additively manufactured polymer with specific structure and characteristics. Crum also assists her group on characterization and infrared spectroscopy projects. Both she and Parker are partly funded through the Director’s Office.

Rockward stated that CMaES and similar programs run by Los Alamos and partner laboratories have allowed more students from underrepresented educational institutions to experience the national lab setting, and have given laboratories new locations from which to recruit. He plans to expand the program further by inviting more colleges, universities, and students to participate. Technical contact: Tommy Rockward

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Intelligence and Space Research

Novel concept for satellite identification and tracking developed

earth with satellites

The computer-generated image shows objects that NASA is currently tracking in Low Earth Orbit. Most of the dots (95%) represent satellites no longer in use. Credit: NASA

As satellite use becomes increasingly pervasive, low Earth orbit (LEO), the altitude range 100–1,240 miles above the Earth's surface, is becoming more crowded. With an increased need to track and identify satellites and space debris in densely populated LEO, astrophysicist David Palmer (Space and Remote Sensing, ISR-2) began formulating an idea for identifying and tracking satellites. This novel concept, an electronic license plate for satellites dubbed ELROI (Extremely Low Resource Optical Identifier) is now closer to becoming a reality. ELROI will be sent into space for the first time through a collaboration with the New Mexico Institute of Mining and Technology (NMTech). Incorporated into NMTech’s satellite, this will be the first iteration of ELROI sent into space for testing and evaluation.

The Los Alamos team began development of ELROI as part of a Laboratory Directed Research and Development (LDRD) project to track space objects and predict their orbits based on better atmospheric modeling and tracking using high-speed cameras. The investigators first tested the concept locally between the Pajarito ski hill and the radio dish, a distance of 15 km, using an early laboratory prototype.

ELROI’s current hardware is lightweight, smaller than a paperback book. A 14-inch telescope with precision filtering detects the photons emitted from ELROI. A thousand times a second, based on ticks of its internal clock, the ELROI beacon either flashes (a “1”) or doesn’t flash (a “0”) its laser diode in pulses a microsecond long to indicate the satellite’s binary registration number. The receiving telescope views the satellite through an optical filter tuned to the precise wavelength of the red laser diode, blocking all other colors of light from sunlight bouncing off the satellite. A high-speed camera records the time of each photon that passes through the filter. These photons include some sunlight that happens to be at exactly the right wavelength. Observation of sets of photons that are an exact integral number of ticks apart enables researchers to determine which photons are from the beacon and discard 99.9% of the sunlight background. Because the beacon repeats its 127-bit registration number approximately 8 times a second, the observer can deduce which bits are “1” and which are “0” over the course of a few minutes of satellite tracking. Error correcting codes allow accurate reconstruction of the registration number even if some of the bits are incorrect or uncertain. As a result, even the dim light from a thousand kilometers away will provide a confident satellite identification.


ELROI, the tiny, laser-powered license plate to fit on satellites headed for space.

International Law governs satellites and debris in space (“space junk”) in orbit around the Earth. Space debris results from retired satellites, rockets, and satellite fragments (e.g., solar panels, batteries, and fuel tanks) produced by collisions. Each collision then creates more debris which increases the chance of additional collisions. If an active satellite collides with debris, the results are often catastrophic and expensive.

With ELROI on board, if a collision was imminent, the owner could be identified and notified to modify the satellite’s orbit to avoid what could be a debilitating collision. ELROI could have additional advantages. Today, it is very difficult to identify each of the hundred satellites a rocket has just released. A satellite with GPS on board can tell the ground “I’m the one at this location”. However, GPS increases costs and requires a significant amount of a satellite’s power just to radio the information to Earth. ELROI uses a minimal amount of solar power provided by its own small solar cell that measures only a few square centimeters (less than a square inch).

The Lab’s patent-pending technology not only has the ability to blink out its serial number, it could also be programmed to communicate additional information valuable to satellite operators. ELROI could be programmed to blink out knowledge of the satellite’s health, acting as a “black box” if something goes wrong with the spacecraft. If the operator knows whether the satellite is powered and its radio is operating correctly, a satellite that never calls home could be diagnosed and possibly fixed much more easily.

ELROI’s blinking light would not interfere with the radio waves. Traditionally, once a satellite’s useful life is over, the power is turned off and its radio is silenced to enable other satellites to use the same frequencies. Because ELROI is fully self-contained, it could continue to blink its serial number without the satellite’s computer and radio being powered on.

The launch of NMTech’s satellite with ELROI aboard is planned for later this year. Once launched, ELROI will stay in orbit for about a year before the CubeSat burns up in the Earth’s atmosphere. During that time, Laboratory scientists will research ELROI’s operations to improve efficiency and increase capability. The Los Alamos team is also working to miniaturize ELROI to the size of a postage stamp and expand its black box capability.

mini ELROI

Laboratory scientists are working to miniaturize ELROI to the size of a postage stamp.

As satellites become smaller and more affordable, Earth orbit may soon become unsafe for satellite research and the commercial LEO satellites used for Internet, Earth observing, etc. These satellites will become both the main victims and sources of debris from collisions. Moreover, industry and government agencies are making the move to CubeSats, miniaturized satellites most commonly used for space research. CubeStats are far more cost effective for experimental use in LEO than traditional satellites, and hundreds can be launched at a time to form large constellations. These constellations are used for various missions including expanded communications and Internet access, and Earth imaging used to examine day-to-day changes in crops, bodies of water, and infrastructure. The Inter-Agency Space Debris Coordination Committee recommends tracking devices be added to all satellites. ELROI’s novel “license plate” capability, coupled with new satellite methods designed to reduce debris in space, is the future of safer, cleaner, and more responsible satellite activity in the superhighway of space.

The Los Alamos team includes: David Palmer (Space and Remote Sensing, ISR-2), Charles Weaver (Space Electronics and Signal Processing, ISR-4), and Rebecca Holmes (Space Science and Applications, ISR-1). Researchers presented ELROI at the 9th International Space Safety conference.

The Laboratory Directed Research and Development (LDRD) Program followed by Laboratory Pathfinder funding sponsored the project. The NMTech CubeSat will be launched as part of the NASA Educational Launch of Nanosatellites Program. The research supports the Lab’s Global Security mission area and the Integrating Information, Science and Technology for Prediction and Science of Signatures science pillars through the development of remote sensing for situational awareness in space. Technical contact: David Palmer

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Materials Physics and Applications

Stress in 3-D nanoarchitectures distributes throughout core and shell

At fast charging rates, lithium ion battery anodes with silicon (Si) core and germanium (Ge) shell nanowire heterostructures have a higher storage capacity compared to anodes with Si nanowires alone. However, defect propagation limits the performance of these higher capacity lithium ion batteries. Center for Integrated Nanotechnologies (MPA-CINT) researchers and collaborators investigated the cause of this phenomenon and found, for the first time, that stress in a core/shell nanowire heterostructure is shared between the core and the shell. The journal Nanoscale published the findings.

The researchers performed an integrated study of structural characterization and electrochemical performance to determine the root cause of the defect propagation. The team showed that radial heteroepitaxial shell growth induced structural defects in the core nanowires, which relaxed strain in both the core and shell regions. The distributed stress in the shell and core differs from conventional thin films on substrates, where the stress is confined in the thin film. The induced structural defects affect the electrochemical performance of the combined core/shell nanowire heterostructure. The investigators suggest that the induced defect in the core/shell structures causes the actual capacity of the lithium ion battery performance lower to be lower than the theoretical maximum. The induced defects observed in the research are crucial factors to be considered for nanodevices and battery electrode design.
Defect-free single crystalline Si nanowires

Defect-free single crystalline Si nanowires generate structural defects from stress when the Ge shell becomes thicker. The short lines in the Ge shell represent the induced defects. NW is nanowire.

This work is the first observation of how strain relaxation in 3-D structures of nanomaterials impacts electrical energy storage. The concept of crossover defects provides a new tunable parameter and a novel factor for designing nanomaterials that improve electrical energy storage.

The Si/Ge core/shell nanowire heterostructure serves as a representative platform for these types of composition modulation studies. The team concludes that this type of strain relaxation in 3-D nanostructures, which does not occur in conventional thin films, should be considered in designing nanomaterials for nanodevices.

Reference: “Strain-Induced Structural Defects and their Effects on the Electrochemical Performances of Silicon Core/Germanium Shell Nanowire Heterostructures,” Nanoscale 9, 1213 (2017); doi: 10.1039/C6NR07681E. Authors: Researchers: Dongheun Kim, Nan Li, and Jinkyoung Yoo (Center for Integrated Nanotechnologies, MPA-CINT); Zhen Li and Shixiong Zhang (Indiana University – Bloomington); Binh-Minh Nguyen and Yung-Chen Lin (formerly MPA-CINT).

The research was performed in part at CINT, a DOE Office of Basic Energy Sciences User Facility jointly operated by Los Alamos and Sandia national laboratories. The DOE Basic Energy Sciences and its Scientific User Facilities Division funded the Los Alamos portion of the study. The work supports the Lab’s Energy Security mission area and its Materials for the Future science pillar. In studying the fundamental properties of materials, researchers aim to tune those properties and achieve controlled functionality, a central vision of the Laboratory’s materials strategy. Technical contact: Jinkyoung Yoo

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Materials Science and Technology

Plutonium surface mechanical properties measured

The surface of a material carries valuable information about its preparation techniques, which in turn affects its further evolution with time and interaction with ambient conditions. Properties of the surface of plutonium (Pu) are of particular interest to researchers because understanding its transformations significantly contributes to the Laboratory’s stockpile stewardship mission.

A Lab team used atomic force microscopy (AFM) with peak-force quantitative nanomechanical mapping (PF-QNM) modality to examine Pu coupons with mechanically polished surfaces. The results revealed a fascinating pattern of elastic deformation of the Pu surface induced by the AFM probe, which was absent in standard surface topography imaging. The peak force error image represents Pu surface topography displaying random polishing induced straight groves and scattered dust particulates. The simultaneously collected deformation image consists of ordered alternating bright (regions of greater deformation or softer material) and dark regions of approximately 2 µm width running through the sample length. As time passed and the Pu surface oxide had built up, the striations became less prominent and faded away.
(Left): Peak force error image representing Pu coupon surface morphology and (right): Pu surface deformation image obtained by PF-QNM technique.

(Left): Peak force error image representing Pu coupon surface morphology and (right): Pu surface deformation image obtained by PF-QNM technique.

Understanding the cause of these striations’ appearance and extinction will enable studies that relate the mechanical properties of Pu surfaces to intrinsic reactivity and aging behavior of this material. The team performed measurements on mechanically polished and unpolished stainless steel coupons for comparison with Pu. The researchers did not observe striations on the cut stainless steel surface, whereas striations similar to the ones observed on Pu formed after the stainless steel surface was mechanically polished. The investigators concluded that surface processing (i.e., mechanical polishing) leaves a characteristic time variant imprint on Pu surface mechanical properties, which is veiled from observations by bulk mechanical properties studies.

Team: M. Beaux, M. Santiago-Cordoba, N. Leon-Brito, and I. Usov (Engineered Materials, MST-7); M. Ramos and J. Gallegos (Nuclear Materials Science, MST-16). Researchers presented the study at the Materials Science & Technology Technical Meeting (MS&T17) in Pittsburgh, PA.

This advance in understanding resulted from NNSA Science Campaign 1 investment (Tom Venhaus, Bill Blumenthal, and Ray Tolar) in the scanning probe microscopy capabilities within the Pu Surface Science Laboratory. First observations of these striations were made during the late stages of an Laboratory Directed Research and Development (LDRD) project (Exploring Mechanisms of Catalysis on Plutonium Surfaces, Marianne Wilkerson, Principal Investigator). This work supports the Laboratory’s Nuclear Deterrence mission area and the Materials for the Future science pillar. Technical contact: Miles Beaux

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Mesoscale Materials Science on the Roadmap to MaRIE

Advanced Photon Source studies reveal phase and microstructure evolution of U-6Nb

The uranium-niobium system (U-Nb) is a complex material system with numerous competing stable and metastable phases as a function of temperature and composition. Alloys near 6 wt% Nb, aka U-6Nb, exhibit remarkable corrosion resistance and ductility for defense applications. A common issue of concern in these applications is the impact of long-term aging, thermal excursion, and mechanical perturbation on these and related properties. Such concerns have motivated a wide range of aging studies of U-Nb alloys at the Laboratory over the last two decades.

One area of the R&D efforts has focused on thermally activated aging of U-6Nb over the 300-647 °C range. The ex situ metallography measurements show that the initial aging involves general precipitation that forms non-lamellar microstructures with the composition of the body centered cubic (BCC) γ phase in the 20-50 at% Nb range. As aging continues, the microstructures are replaced with a fine lamellar spacing (greater than 40 nm), called discontinuous precipitation. The final equilibrium state is achieved with a secondary reaction that replaces the fine lamellar microstructure with lamellae that are 5-10 times coarser, and with a change in γ-phase composition that approaches approximately 75 at% Nb.

In this work researchers combined x-ray diffraction and small-angle x-ray scattering (SAXS) measurements of U-6Nb at elevated temperature up to 523 °C to monitor the early transformation processes in situ and in real time. They determined for the first time the crystallographic details of phase separation with sub-second time resolution, including phase evolution, lattice parameters, and solute (Nb) redistribution in the γ phase. Their experiments also reveal complex martensitic transformation paths leading to diffusional phase decomposition, observations that are not attainable at longer time scales. The simultaneous SAXS measurements allowed determination of the time dependence of nucleation, growth, and coalescence of α-uranium domains. This information enabled the team to derive information about the microstructure evolution during isothermal aging.


Fine-scale changes in phase fraction

Fine-scale changes in phase fraction, solute composition (at% Nb in γ1-2), and the size (radius of gyration, Rg) and relative number of α-U domains derived from time-resolved diffraction (left panel) and SAXS (right panel) data analysis of U-6Nb at an isothermal temperature of 523 °C.

The phase fraction data indicate two different kinetic stages of phase separation associated with general precipitation and domain growth. The team used phase compositions obtained from diffraction analysis to determine the electron density contrast (∆ρ2) and, assuming spherical domain shapes, combined with the SAXS analysis to determine the relative number of domains. The researchers determined that the average domain volume increases proportionally to t1/3 while the decreasing number of domains indicates coalescence.

Next-generation light sources such as the Advanced Photo Source at Argonne National Laboratory, where this work was performed, offer a novel method to probe a material’s microstructure at the mesoscale, the scale between the atomic and integral key to understanding and controlling many of a material’s properties and its performance. Use of the sub-second time resolution offered by the Advanced Photon Source to make combined x-ray diffraction and SAXS measurements is a unique approach to complement ex situ metallography measurements for monitoring the evolving microstructure. The fine-scale characterization of the simultaneous changes in phase evolution, solute composition, and lamellar microstructure is essential for understanding aging mechanisms and establishing the underlying kinetic models.

Such time-resolved information is also important for developing new manufacturing routes, such as additive manufacturing, for U-Nb components. Los Alamos National Laboratory’s proposed MaRIE (Matter-Radiation Interactions in Extremes) capability would take this research further by resolving in 3-D the chemical and crystallographic details of the lamellar growth interface region as the phase transformation actually happens. Migrating interfaces such as these have been theorized and modeled since the 1940s, but little has been measured by in-situ time-resolved methods, especially in 3-D, which provides a more stringent test and validation of predictions of microstructural evolution.

Researchers: Donald Brown, Bjorn Clausen, Adrian Losko, Reeju Pokharel, and Jianzhong Zhang (Materials Science in Radiation and Dynamics Extremes, MST-8); Erik Watkins (Materials Synthesis and Integrated Devices, MPA-11); and Robert Hackenberg (Sigma Division, Sigma-DO). NNSA Science Campaign 4 and the Enhanced Surveillance program funded the work, which benefited from the use of the Advanced Photon Source of Argonne National Laboratory (funded by the DOE’s Office of Science, Office of Basic Energy Sciences). The research supports the Lab’s Nuclear Deterrence mission area and the Materials for the Future and Science of Signatures science pillars through observation and understanding the thermally activated aging of U-6Nb. Technical contact: Jianzhong Zhang and Erik Watkins

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Additive manufacturing produces the first scale model of a nuclear reactor core component

According to the Nuclear Energy R&D Roadmap Report submitted to Congress in 2010, two key challenges facing the nuclear energy industry of the future involve: 1) making improvements in the affordability of new reactors, and 2) developing structural materials to withstand irradiation for longer periods. Laser additive manufacturing (AM) is particularly well suited for more rapid and economical fabrication of reactor components relative to current methods. Moreover, the rapid thermal cycles associated with laser AM have the potential to improve the radiation tolerance of certain alloys used for reactor applications. Los Alamos researchers have made significant strides in laser AM of reactor components.
Subscale heat exchanger component for the nuclear reactor core

Subscale heat exchanger component for the nuclear reactor core. The hexagonal-shaped component is approximately 9 inches across and about 2 inches deep. It was fabricated from Grade 91 steel powder in a powder-bed AM process and took about 90 hours to build.

One of the achievements involved producing a subscale heat exchanger component for the core of a small modular reactor as a technology demonstration for AM. The team fabricated a heat exchanger component using a powder bed fusion-laser AM machine from Grade 91 steel powder. Grade 91 steel is a second-generation creep-resistant steel with improved radiation tolerance relative to earlier alloys. It is employed widely in fossil and nuclear power plants in both plate and pipe forms for components operating at temperatures up to approximately 650 °C. Grade 91 is the current “workhorse” alloy in these applications and was approved for use under the ASME Boiler and Pressure Vessel Code in 1983. Other tasks within the study included characterization of the AM microstructures, testing the mechanical properties, and irradiation testing.

The researchers believe that this effort is the first to examine fabrication of nuclear reactor components using AM. Results demonstrated that AM can be used for affordable fabrication of reactor components from Grade 91 steel with appropriate radiation tolerance. These findings indicate the potential to transform fabrication methods for reactor components made from radiation tolerant materials with increased affordability and faster implementation schedules.

Researchers: Robin Pacheco, Mike Brand, and Tom Lienert (Sigma Division, SIGMA-DO); Stu Maloy, Eda Aydogan, and Ben Eftink (Materials Science in Radiation and Dynamics Extremes, MST-8); Terry Holesinger, Matthew Janish, and Todd Steckley (Nuclear Materials Science, MST-16).

The Laboratory Directed Research and Development (LDRD) Mission Foundations Feasibility Studies program funded the work under the topic area of Exploiting Additive Manufacturing for Fabricating Radiation-Tolerant Nuclear Components. The Civilian Nuclear Power Program Office championed this topic area. The research supports the Lab’s Energy Security mission area and the Materials for the Future science pillar through the ability to fabricate components for nuclear reactors. Technical contact: T. J. Lienert

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Impact of Antarctic basin-scale precipitation on surface ice mass variability modeled

The Antarctic ice sheet is the largest continuous ice complex on the planet. Precipitation in the form of snow is the major means by which the ice sheet gains mass. The dominant term of the Antarctic ice sheet surface mass balance displays large spatial and temporal variability.

Due to the massive size of this ice sheet, even small changes to snowfall can have significant impacts on global sea level changes. A research team, including lead Jeremy Fyke (Fluid Dynamics and Solid Mechanics, T-3) of the Laboratory’s Climate, Ocean, and Sea Ice Modeling Program (COSIM), analyzed spatial patterns of regional Antarctic precipitation variability and their impact on integrated Antarctic surface mass balance variability. The investigators performed simulations as part of a preindustrial 1800-year global, fully coupled Community Earth System Model simulation. Correlation and composite analyses based on this output enable a robust exploration of Antarctic precipitation variability. The journal The Cryosphere published the research.

Basin-specific coloring

Basin-specific coloring: inter-basin annual integrated precipitation zero-lag correlations for basins 2, 7, 14 and 19 (in green). Stippling represents the presence of inter-basin significance at the 95 % level. Arrows: vector differences between basin-specific composite vertically integrated moisture transport climatologies (high minus low basin-specific integrated precipitation).

The team identified statistically significant relationships between precipitation patterns across Antarctica that are corroborated by climate reanalyses, regional modeling, and ice core records. These patterns are driven by variability in large-scale atmospheric moisture transport, which itself is characterized by decadal to centennial scale oscillations around the long-term mean. The research identified significant countervailing snowfall patterns between ice sheet drainage basins (analogous to watersheds), with higher snowfall in one location often strongly counteracted by lower snowfall elsewhere. Coherent relationships extend to very remote basins on either side of the ice sheet. The investigators conclude that the coherent heterogeneity in Antarctic precipitation variability has a strong dampening effect on overall Antarctic surface mass balance variability. This finding has important implications for regulation of Antarctic-sourced sea level variability, detection of an emergent anthropogenic signal in Antarctic mass trends, and identification of Antarctic mass loss accelerations. The paper was selected as a European Geosciences Union “Highlight Article” and is currently featured on the EGU website. Fyke presented the paper at the American Geophysical Union (AGU) annual fall meeting in December 2017.

Reference: “Basin-scale Heterogeneity in Antarctic Precipitation and its Impact on Surface Mass Variability,” The Cryosphere 11, 2595 (2017); doi:10.5194/tc-11-2595-2017. Authors: Jeremy Fyke (Fluid Dynamics and Solid Mechanics, T-3), Jan T. M. Lenaerts (University of Colorado and Utrecht University), and Hailong Wang (Pacific Northwest National Laboratory).

The DOE Office of Science, Biology and Environmental Research, Regional and Global Climate Model Analysis via the High Latitude Application and Testing of Earth System Models project funded the research. The work supports the Lab’s Energy Security mission area and the Science of Signatures and Integrating Information, Science and Technology for Prediction science pillars through the ability to model Antarctic precipitation and ice mass variability. Technical contact: Jeremy Fyke


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