DOE/NA-0023

Office of Research, Development, Test, and Evaluation Stockpile Stewardship Quarterly

VOLUME 4 | NUMBER 2 | JUNE 2014

essage from the Assistant Deputy Administrator for Research, M Development, Test, and Evaluation, Dr. Kathleen Alexander t is with great on a wide range of experimental pleasure that platforms. A key experimental I EarlyRoot ofCareer Sandia Award National in Science Laboratories message for the and(SNL), Engineering; was awarded SNL a researcherPresidential StockpileI craft Stewardshipmy first capability for stockpile stewardship Stephanie Hansen received an Early Quarterly. I am measuringis the 40-mm the Impact dynamic Test properties Facility at of honored to lead Los Alamos National Laboratory for this organization plutonium data for more than 18 ourCareer Carnegie-DOE Research Program Alliance award Center from that performs plutonium. This facility has provided AcademicDOE’s Office Partners, of Science; Professors and two Steven of work crucial to high-foot implosion campaign on the success of the Defense Programs’ years. The technical article on the Eva Zurek (University at Buffalo, State Jackson (Northwestern University) and the National Ignition Facility (NIF) prestigious awards as well. science,mission. technology,I have confidence and engineering in the ability physicaldescribes phenomena exciting recent occurring experiments in University of New York) have received solutionsof the enterprise to the mission to deliver challenges the best designed to better understand key

time on improving communications polar-drivethe NIF indirect-drive experiments capsules. on OMEGA The at workingFinally, to with all members all of you ofand the leading NNSA this withbefore our us. stakeholders I will be focusing regarding a lot ofthe my final technical article describes recent organizationRDT&E community: as we take I look on forward the exciting to importance and impact of the NNSA whichthe University were designed of Rochester to understand Laboratory thefor Laserphysics Energetics occurring and in direct-driveon NIF, challenges before us. mission.Office of Research,In addition, Development, I am committed Test to ensuringand Evaluation the health (RDT&E) and vitality on our ofcore the x-ray drive. implosions at facilities configured for One of the most rewarding elements RDT&E enterprise. of our program is to provide Inside 2 The Role of Computing in Stockpile In this issue, you will find articles which opportunities to students through the Stewardship Science Academic Stewardship thespan experimental the breadth ofscience activities performed in the 6 250 Shots and Counting! The 40-mm RDT&E portfolio—from computing to Impact Test Facility at Los Alamos energy density physics researchers National Laboratory’s TA-55 throughAlliances the (SSAA) High programEnergy Density and to high at our national laboratories and at 8 The High-foot Implosion Campaign rolean affiliated of computing university throughout facility. theThe on the National Ignition Facility computing article describes the critical Information on those opportunities history of the Stockpile Stewardship Laboratory Plasmas grant program. 10 Polar-drive Implosions Results from Program. OMEGA and the National Ignition issue of the Stockpile Stewardship Facility can be found on the final page of this Validation of our modeling and Quarterly. Of particular note is that 12 Highlights and Awards one of our past SSAA participants, Seth

simulationComments capabilities is performed The Stockpile Stewardship Quarterly is produced by the NNSA Office of Research, Development, Test, and Evaluation. Questions and comments regarding this publication should be directed to Terri Stone at [email protected]. | Technical Editor: Dr. Joseph Kindel | Publication Editor: Millicent Mischo 2

The Role of Computing in Stockpile Stewardship by Bill Archer, Robert Webster, Mark Anderson, Jon Boettger, and Fred Wysocki (Los Alamos National Laboratory); Christopher Clouse (Lawrence Livermore National Laboratory); and Kenneth Alvin and David Womble (Sandia National Laboratories)

Why Simulations? Since the introduction of punch card for re-entry systems and for the safety accounting machines in the Manhattan Project in 1944, simulations have needThe Stockpile for nuclear Stewardship testing as aProgram means to and security of systems in abnormal ensure(SSP) has the been safety developed and performance to avoid the of the playsenvironments, a strong role e.g., incrash, exploring fire, lightning, the stockpilebeen used was to assist only tested in making in a veryweapon or blast. In all of these cases, simulation Stockpile Stewardship Quarterly Volume limitedperformance regime decisions of the stockpile-to- because the cycles, assessing performance, designing enduring stockpile. As described in the tests,design and space assuring and reducing the safety build-and-test and on a set of new experimental facilities testing, the only way to evaluate the security of the stockpile. for4, Number understanding 1 (May 2014)dynamic issue, performance it is based performancetarget sequence. impact Today of awithout change nuclear to the device is through simulation. Without of materials and a simulation capability experimentally explore the entire range The use of simulation also helps sustain considerably more predictive and ofnuclear physical tests, conditions it is not possiblethat exist to in a the knowledge-based deterrence called higher fidelity than the simulation tools thatfor in is the used 2010 to recruit, Nuclear educate, Posture and Review. With the end of nuclear testing, it was available during nuclear testing. retainSimulation new nuclearcapability weapon is a major designers. tool realized that computer simulation would nuclear weapon. The temperatures, have to, in essence, form a numerical material in a nuclear explosion, for pressures, and scale experienced by using simulations to carry out what-if Today, stewards are trained, in part, by nuclear experiments, would allow us to scenarios to see how changes affect test base that, along with focused non- example, cannot be simultaneously performance and to gain physical SSP uses simulations to help weapons accessed by any experimental facility. insight into the impact of changes to the avoid a return to nuclear testing. The plays an important role in reducing costs andEven improving where tests the are performance possible, simulation and What is fullstewards lifetime make of a decisions nuclear weapon; about the from safety of weapons systems. Costs limit performancea Code? of a device. The integrated stockpile. These decisions span the designAdvanced codes Simulation (IDCs) (see and the Computing to the performance impact of aging experiments involving the use of special sidebar) developed under the parts,performance to the one-point impacts of safety a refurbishment, of tooling nuclearthe manufacturability material. Costs and also availability limit the of complex tools requiring complex input, and(ASC) a masteryprogram of for the use use by of stewards these tools are configurations for dismantlement. number of tests that can be performed What Is a Code?

An integrated design code is the collection of instructions to solve the many different types of physics involved in a nuclear The term “code” refers to a collection of instructions that tell a computer what to do, as shown in the code snippet (see Figure 1).

weapon. Many of our codes work by breaking the problem down into small spatial pieces, called mesh cells, as shown in the setup of a shape charge (see Figure 2). The simulation time theis also simulation. subdivided Some into types pieces, of codescalled aretime more steps. accurate Each piece for simulating of physics solidis solved materials within while each cell during each time step. The code numerically follows the physics through time to solve

other types of codes are more accurate for simulating the turbulent flow of liquids and gases. The numeric methods used to solve the physics also introduces different types of errors. For example when applied to a particular type of physics, one code method will introduce ASCstatistical program noise provide into the solution, whereas another method will cause spatial hot spots. The acodes complementary supported by set the of methods to allow us to understand the strengths and weaknesses of different types of codes and methods on each

charge, showing the simulation situationparticular where problem. one Figure 2. Setup of a shaped This is definitely a each cell over an entire mesh. Figure 1. Snippet of code instructions to calculate internal energy in mesh (By Daniel Ingraham). size does not fit all! Volume 4 | Number 2 | June 2014 Stockpile Stewardship Quarterly 3 the steward and adequate peer review Equation-of-State (EOS) Modeling requires both hard work on the part of by other stewards. In addition, many of Simulations of nuclear devices require tabular EOSs that represent all materials in the basic algorithms developed within overthe system. a wide Therange reliability of compression of such simulations(104 is sensitive to the9 fidelity of those the SSP are employed in unclassified EOSEOSs. models The challenge used are is tuned to produce to match tabular experimental EOSs that data are accurateand results and from well-behaved atomistic internationallycodes for use on peer unclassified reviewed, problems thus simulations. Until recently, a well studied) and material temperature might have(10 ).data To thisalong end, the the room where results can be published and ourproviding stewards. additional scientific credibility, temperature isotherm up to 1 Mbar (purple in Figure 1), the principal Hugoniot to and a critical test of the capabilities of a few 10s of Mbar (solid black line in Figure 1), and some Hugoniot data on porous How Do We Simulate? samples. None of this data can be used to constrain an EOS in the high pressure, Simulations are the end result of a low temperature region probed by an imploding shell of material. This led the laboratories to depend on tuning the most important EOSs to match Nevada Test couple together many different pieces Site events. Such tuning was a reasonable expedient during the era of testing, oflarge physics scientific to provide enterprise. the simulation The IDCs but is impractical today. Over the last fordecade, generating however, data this along picture isentropes, has been altered by the introduction of techniques shows are needed to simulate a nuclear capability that decades of experience dashed lines in the Figure 1 (data from Z makes the IDCs different from most weapon system. This integration Machine, laser drive), quasi-isentropes (data from graded flyer gas gun) or in withan imploding atomistic shell simulations, which do have probe played that scientific codes that focus on doing only infrastructure is designed to support anregion. important These rolenew in capabilities, creating a newalong one or two types of physics. The IDC physics model evolution, over time multi-phase EOS for Pu at LANL that adding more detailed physics to the compares well with multiplexed photon models, resulting in improved predictive Doppler velocimetry data from recent models. Figure1.experimentally. EOS of gold, showing the EOS regions that can be measured subcritical experiments at U1a. are used to simulate the entire range ofThe nuclear IDCs are security very general questions codes asked that to experiments, underpin all of the designer judgment with the IDC through integrated design simulations (see the Equation-of-state (EOS) Modeling of the laboratories. For example, on the use of empirical calibrations, any given day the same IDC can be colloquially known as knobs. Assessmentused to simulate of all issues stockpile for Significantsystems, sidebar above). andTraditionally, were only the valid calibrations for closely were related forFinding ongoing Investigations, Lifetime Extension for the Annual tests.set to Eacha small family number of devices of nuclear had itstests areThe used SSQ Marchto inform 2014 physics issue theorydiscussed and the role of experiments. The experiments the nominal range of performance. proliferantProjects (LEPs), nuclear and weapon, for non-stockpile foreign Computational physicists turn the own calibrations that were valid for weaponapplications design like assessment, disablement or of nuclear a modelsmodels, intoand numericalthen to calibrate methods the that models. are forensics, in which a design is inferred implemented in the IDCs. Experimental The lack of a universal set of empirical from post explosion data. data is used to validate the models, calibrations was acceptable because producing, in the end, a validated changesWith the to end devices of nuclear could testing, be tested. the lack the IDC suchThere as are particle also science transport, codes material that simulation tool for use by stewards. of predictive capability by propertiesspecialize in at a the particular quantum physics level, orproblem high became a problem. For example, the requiresIn the end, rigorous confidence comparison in the simulation of relevant testingknobs were the question calibrated of towhere nominal the in the development of theory, models, simulationsresults is vital. to ongoingBuilding experiments, that confidence and failureperformance, point is but for with each the type end of ofweapon andexplosive computed burn. properties These codes that are are used historical nuclear tests. needed within the SSP. In addition, these exactly where nuclear test experience specialized codes provide a framework Are We Done? became very important. Yet, this is for incorporating experimental data and extending our knowledge to shows that the calibrations are least ofAt athe nuclear end of weapon nuclear existed.testing inHowever, 1992, a reliable. In addition, there were many with current experimental facilities. broad understanding of the functioning nuclear tests whose behavior was never Dataconditions on the beyond properties what of can materials be reached is anomalies.understood, In either general, by experimentsthe presence or a particularly important area where lackquestions of understanding remained about of these the details simulations; these tests are labeled theory and specialty codes, in addition of some physicalincorporating interactions. Theexpert uncertainty when simulations are of the empirical calibrations causes was handled by Office of Research, Development, Test, and Evaluation Volume 4 | Number 2 | June 2014 4

What Is Fidelity? idelity means accuracy, exactness, or adherence to fact or detail. High F

nation’sfidelity simulations nuclear stockpile. are necessary Simulation to predict the safety and reliability of the

physicsfidelity canincluded be measured in the simulation, in at least three ways:detail 1) and the precision correctness of the of the geometric representation of the system 2) the the numerical algorithms used to solve thebeing approximate modeled, and equations. 3) the accuracy of High performance computing

has enabled much higher fidelity simulations by addressing all three of morethese spatialaspects zones of fidelity. to represent Obviously, a resolution can be increased by the use allows for a more accurate geometric description.system on a largerSimilarly, computer. faster computers This also Figure 1. Turbulent flows highlight the need for higher fidelity simulations to address permit smaller time steps or more problems of interest (By David Livescu).

associatediteration in with approximate simulation solution, of nuclear thereby weapons. increasing their accuracy. Perhaps the most promising of the fidelity enhancements afforded by high performance computing is the ability to support more complete and correct representation of the physics

Next Generation Systems and Codes

The high performance computing industry has seen many changes since its suddenly.inception Duringfollowing the the modern Second supercomputer World War. From era, switches at least two to punch instances cards of to data centers to supercomputers, change has occurred both gradually and

sudden change have already occurred: the introduction of vector computers in asthe computer 1970s, and chips the reachappearance physical of limitsmassively on size parallel and voltage. clusters in the 1990s. The industry is now on the brink of another such change in processor technologies Roadrunner purposeThe coming graphics paradigm processors shift is inexpected addition to to involve general many purpose processing central elements processing on a single die and, possibly, heterogeneous processing elements, e.g., general

NNSAunits. Suchis investing technologies in exploring challenge technologies the ability such of the as IDCsthese to for deliver application timely to stockpilesimulations stewardship. for the stewards. To prepare for the future, the ASC program at

The Roadrunner supercomputer at Los Alamos National Laboratory was experimentan exploration in manyof heterogeneous homogeneous computing cores computing. architecture. Both The computers Sequoia are supercomputer at Lawrence Livermore National Laboratory is a current programmers in the future. harbingers of the challenges facing computer scientists and application

Sequoia Other challenges are beginning to appear, such as power requirements and intentlower availableof this program memory element per core. is to ASC respond has created to the ashifting new program technology element, landscape to insure that NNSA will continue to have leadingAdvanced edge Technology supercomputers Development and critical and Mitigation simulation to software address theseto support issues. stockpile The stewardship.

Volume 4 | Number 2 | June 2014 Stockpile Stewardship Quarterly 5

pushed beyond the calibration regime. The further the extrapolation, the more uncertain results become. of stockpile stewardship are evolving fromAdditionally, those asked the questions during the being Cold askedWar. One reason for this is that stockpile weapons have been in service well beyond their designed lifetimes ranging from 10 to 30 years and aging effects that understandwere never testedthe aging are ofnow materials becoming in theprevalent. devices This to determine drives stewards when an to LEP simulations are the frequent three- is required. Further complicating the component aging. Due to aging, LEPs dimensional (3D) effects associated with nuclear and the non-nuclear components ofhave the been weapon required systems. to rework During both LEPs, the Figure 1. Computing power of LANL computers since 1944. the effect on performance of replacement materialssimulations and must new be technology used to understand such supercomputer is located at the SCC as redesigned arming, fusing, and broad set of the stockpile devices. This Cielo, a Cray XE6 1.4-petaflops whengives the they stewards are applied increased to analysis confidence and and SNL staff. Cielo is routinely used in the predictive capability of their tools and is operated for the tri-lab by LANL firing subsystems, and to determine if redesigned components meet reliability listcertification of historic of anomalies, LEPs. Modern again simulation increasing SCCfor 3D also simulations house smaller that computerspush the edge that desirerequirements to improve in now-untestable safety and security, capabilities have also solved a growing areof predictive used for the science. routine Both stewardship the TSF and radiation environments. The continuing tools. high explosives with insensitive high the confidence the stewards have in their performance computers that will such as by replacing conventional replacework. The Cielo next and generation Sequoia are of high expected simulations to predict performance. codes increases the amount of Improving the fidelity of the weapon explosives, also stresses the ability of computational work and memory in architectures, which will impact the IDC each simulation. Providing the stewards (seeto have the significantly Next Generation different Systems internal and The SSP has made great progress in Codes theimproving What Is our Fidelity? simulation capability. increasedwith acceptable capacity execution of the computers times for sidebar). onImproved computers fidelity with weapon greatly codes increased (see higher fidelity simulations requires run on these massive computers sidebar) running The integrated weapon codes that experimental facilities such as the driventhat the the simulations 1015 increase run inon. computer This drive scientists working on experiments, capability, combined with data from for increased simulation fidelity has embody the work of a wide range of

Dual Axis Radiographic Hydrodynamic Currentlyspeed shown the inASC Figure program 1, since provides the performancetheory, and modeling. without nuclearThe improved tests Test Facility and Proton Radiography computersbeginning of for the stockpile Manhattan stewardship Project. at ability to simulate nuclear weapon Facility at Los Alamos National of the SSP. Going forward, there are Laboratory (LANL), Z at Sandia National continuinghas been an demands outstanding to improve achievement the forLaboratories Laser Energetics, (SNL), Omega and the Laser National Facility two main facilities: the 253,000-square- at the University of Rochester Laboratory foot Terascale Simulation Facility (TSF) questions regarding the weapons can at LLNL and the 300,000-square-foot simulation capability so that ever harder theIgnition stewards Facility to understandat Lawrence the Livermore cause of Strategic Computing Complex (SCC) National Laboratory (LLNL) have allowed at LANL. Sequoia, an IBM BlueGene/Q staffbe answered, to improve and the decisions codes, and can all be 20-petaflops supercomputer, is located themade. experiments, This challenges theory, the modeling, laboratory one major knob and to make progress at the TSF and operated for the tri-lab on others. The modern codes combined one(i.e., millionLLNL, LANL, compute and cores, SNL) byis currently LLNL. modelswith science-based for simulating physics the stockpile. models have theSequoia, third thelargest first supercomputer computer to have in theover succeededand computers in meeting that support the challenges them. To enabled the development of common world, and is optimized for suites of ofdate, stockpile this scientific stewardship, infrastructure and we has

These common models use one set of challenges as well. ● empirical calibrations to successfully jobs such as those required for common are confident it will meet the future model an increasing number and a very models or uncertainty quantification. Office of Research, Development, Test, and Evaluation Volume 4 | Number 2 | June 2014 6

250 Shots and Counting! The 40-mm Impact Test Facility at Los Alamos National Laboratory’s TA-55 by William Anderson, William Blumenthal, Paul Contreras, Paula Crawford, Charles Owens, Chris Adams, and George Gray III (Los Alamos National Laboratory)

located in the plutonium facility at Los The 40-mm Impact Test Facility, is one of the nation’s key experimental Alamos National Laboratory’s TA-55, material properties of plutonium undercapabilities dynamic for measuringloading conditions. fundamental nuclearIt has been weapons-related a workhorse for experiments the last on18 programmaticyears, completing materials more than (primarily 250 safeguarding, and safety protection againstplutonium) release requiring of radiological accountability, and airborneAn important hazards. goal of the Stockpile a predictive understanding of nuclear Figure 1. The 40-mm glovebox at TA-55. The breech end is in the foreground and the catch Stewardship Program (SSP) is to develop tank is located at the far end of the glovebox. and lifetime assessments that ensure the weapons behavior in support of annual our nation’s nuclear weapons stockpile. Improvementsperformance, safety, in our and modeling reliability and of computational assessment capabilities modelsare made into possible weapons by incorporatingsimulation codes. Aadvanced, challenging physics-based part of this materialtask is to a b pressure,understand strain-rate, how fissile and materials, temperature such as plutonium, behave under the extreme properties of these materials are strongly Figureimpact 2.velocity (a) The and 40-mm tilt diagnostic muzzle with pins. a target, window, and diagnostic hardware; (b) dependentconditions ofon actual their crystaldevices. structure The Front side of a 40-mm target containing a plutonium sample in the center surrounded by (e.g., plutonium exists in six different recovered and recycled from the post- The launcher fires a projectile that (e.g., plutonium) is accountable and is crystallographic phases before it melts shot,consists the of projectile a body (“sabot”) is propelled carrying down phases,at ambient materials pressure), processing the kinetics conditions a flat, disc-shaped impactor. During a Experimentalimpact debris. Configurations (e.g.,of transitions impurity between and microstructural the different in a target holder. Depending on the the barrel and impacts a target mounted Two critical aspects of material models variability), and aging due to self- usingdesired either impact compressed velocity, which helium may or be variationsare the equation-of-state in pressure and (EOS), temperature, which irradiation from alpha/beta decay. up to 1.7 km/s, the gun can be fired includingdescribes phasethe response changes of such a material as melting, to essentialThe dynamic for studying property these measurements effects and is precisely aligned with the target and the properties of each individual developing,obtained using constraining, the 40-mm and launcher validating are topropellant produce (e.g.,one-dimensional gunpowder). shock- The barrel the advanced material models required phase; and the phase-dependent to meet the goals of the SSP mission. the projectile, and time of impact at the targetloading are conditions. measured The using velocity, electrical tilt of strength and how damage forms and constitutive behavior, including material How Does It Work? pins mounted on the target. A massive grows as a material is deformed.

are used depending on the information The 40-mm launcher consists of a thesteel projectile “catch tank” and isthe located fragments directly of the Different experimental configurations measurementsmooth-bore gun diagnostics, comprising all acontained breech targetbehind and the impactortarget and resulting is designed from to the stop EOS, spall, shock recovery, and reverse- and barrel, a target and catch tank, and intense impact event. Nuclear material impactbeing sought, EOS. including normal-impact in a protective glovebox (see Figure 1). Volume 4 | Number 2 | June 2014 Stockpile Stewardship Quarterly 7

Shock Recovery A shock recovery experiment is used to

pulse and release to zero pressure with- outsubject tension, a sample and thento a compressiveallows the sample shock

to be recovered for later analysis. In this configuration, the sample is encapsulated thein a specially-designedaxial loading pulse recovery and concentric assembly ringsconsisting that surroundof a “spall the plate” sample that andremoves dissipate radial release waves. After the velocity record from a spall experiment initial shock-loading impact, the target is Figureon tin showing4. Example features of a VISAR associated surface damage using low-density materials that transition during compression, and “soft-recovered” to minimize extraneous Figure 3. Schematic of the Normal- with: spall (1). materialVelocity recordsstrength, provide (2) a phase a Impacta thinner EOS impactor test configuration. and no window. The SpallIn wealth of information on dynamic actReverse-Impact as a “catcher’s EOS mitt”. test configuration is similar, but with (3)material properties. the sample serves as the impactor and theimpacts Reverse-Impact the window EOS directly. configuration, A capability unique to the 40-mm Impact Test Facility at TA-55 is that the wave provide additional information Normal-Impact EOS sample can be mounted in the projectile onThe the timing properties and structure of the sample of the releaseat high EOS is the most fundamental aspect of theas an reverse-impact impactor, rather EOS than geometry. being the In target—a test configuration known as a material model and is the goal of the is to keep the sample at high pressure this type of experiment, the target is a most common experiment performed pressure. The purpose of the window to avoid complications in the velocity the sample and the motion of the impact transparent window that is impacted by measurement.for as long as possible before release with the 40-mm Impact Test Facility at mitigates complications that occur sampleTA-55 using mounted the normal-impact in a holding plate EOS such test Spall duesurface to wave is observed. interactions This intechnique the sample configuration. The target consists of a In a spall experiment, the primary goal and is particularly useful for precisely is to measure the stress required to measuring the high-pressure sound Athat transparent the sample window, surface such will beas directlylithium dynamically fracture the sample, known speed in the sample. impacted by the impactor (see Figure 2). in contact with the opposite surface New Capabilities for the Future offluoride the sample (LiF) andor c-cut the velocitysapphire, of is the placed impactas the spall EOS strength.experiment, The except experimental that theconfiguration impactor is is usually similar thinnerto the normal- and no will expand the range of conditions window is used, leaving the sample Capability upgrades and new diagnostics sample-window interface is observed questions concerning weapons materials by optical diagnostics, called Velocity probed with the gun, allowing important Interferometer System for Any Reflector surface uncovered or “free” (see to preheat targets was installed, which (VISAR) and photon Doppler velocimetry freeFigure surface3). Shock and thewaves rear produced of the impactor, in the allowsto be addressed. the effects Recently, of temperature a capability (PDV), that measure velocity by changes interactingimpact reflect inside as release the sample waves and off placing this propagatesin the wavelength forward of intoreflected the sample laser light. and it in tension. If the tensile stress is high The impact generates a shock wave that enough, it will generate damage in the differentto be directly crystal measured, structures as wellprior as to the form of voids and/or cracks in the sample experiment.allowing samples An optical to be pyrometerheated into will causesone that motion propagates of the backward sample-window into the until the sample fails and separates impactor. The shock wave in the sample into two or more pieces, producing a wavessoon be in added the samples. for direct Additionally, measurement new timeinterface and speedas it passes. of the Thisprojectile, motion, is used impactorof temperatures designs generated will allow by samples shock tocombined determine with the knowledge pressure, density,of the impact characteristic set of waves that can be and energy in the shocked sample. ofobserved the waves as theyprovide arrive information at the sample- on the histories that are designed to replicate free surface. The shapes and amplitudes to be subjected to complicated loading strength or phase changes, can cause and the stress required to cause fracture Complex behavior, such as material type of the damage (i.e., brittle or ductile) or probe unique physical regimes of allows such quantities as compressive the device. These new capabilities, yieldthe shock strength wave and to exhibitphase transition structure that rings(see Figure that carry 4). In away some radial cases, motions,the sample combined with the ongoing need for allowingmay be surrounded the central byportion concentric of the dynamicbetter understanding loading, will keepof how the weapons 40-mm of the shock wave, a release wave is materials behave under high-pressure pressure to be obtained. After passage into the future. ● recoveredsample to andbe captured studied. by impacting a Impact Test Facility at TA-55 busy well generated from the reflection of the low-density material, so that it can be shock wave off the back of the impactor. Office of Research, Development, Test, and Evaluation Volume 4 | Number 2 | June 2014 8

The High-foot Implosion Campaign on the National Ignition Facility by O.A. Hurricane (Lawrence Livermore National Laboratory)

If you could identify only one key skill sensitive to modeling uncertainties. that a primary or secondary designer ratesbeen achievedof energy in loss the leads laboratory. to a quantitative This to design an implosion that works criterionsimple statement for ignition about that fusion is known power as theand pulse-shapeThe modeling were and directlyassertions tested of less and should possess, it would be the ability Lawson criterion, and it’s important to instability growth with the high-foot to harness an implosion is a key skill understand what 1,2this means. while the integrated implosions 13,14 reliably and as advertised. Being able themselvesverified in radiography continue to experimentsexpress no indications of mix as inferred from hot- because of what an implosion does— spot emission measurements.15 an implosion is a “pressure amplifier” The Lawson criteria is a statement that takes absorbed energy and turns that relates the plasma pressure (P) While our high-foot implosion scales generatedthat energy, in with implosions significant is used energy to simplestand plasma form, confinement the Lawson time criteria (t) to for a loss, into pressure. The pressure criterion that defines ignition. In its compress materials to high densities back from the goal of high gain ignition in the primary designer’s case, and ignition of deuterium-tritium (DT) fusion greatlyby giving exceeded up some past potential implosion compression high densities and temperatures in the of the DT fuel, its performance has secondary designer’s case. While primary canfuel varyis P t somewhat, > 30 atm-s depending(atmospheres upon x designers and their simulation tools plasmaseconds); density although, and temperaturethe exact number (e.g., theperformance fusion yield as exceedsdemonstrated the energy by recent implosions obtaining “fuel gain” (where aroundcan be tested the NNSA against complex, experiments secondary at for lower density but hotter magnetic heating,delivered and to thethe fusionhighest fuel), levels more of Lawson than a scale fielded at high-explosive facilities fusion plasmas, the criteria is about designers are much more limited in the yield doubling due to alpha-particle self- experimental facilities that can access 1/3 of the above value). The Lawson criterion suggests why obtaining ignition pressures of atmospheres, the plasma criteria to date (see Figure 1). is so challenging. For modest plasma relevant conditions. Facilities such as the The data shown in the upper right Energetics,Omega Laser the Facility Z machine at the at University Sandia confinement time must be many 10s of hand side of Figure 1 show that much of Rochester Laboratory for Laser seconds (the magnetic fusion case). For nanosecond, the plasma pressures must challengesprogress towards that remain ignition in orderhas been to push small confinement times of less than a New Mexico, and the National Ignition furthermade, but towards the points the ignition also belie regime. the National Laboratories in Albuquerque, While high performing, most high- be enormous and on the order of many orFacility less it. (NIF) Ignition at Lawrence conditions Livermore are the hundreds of billions of atmospheres (the highestNational pressure Laboratory and, (LLNL) therefore, are morethe ICF case). foot implosions exhibit hot-spots (the hardest conditions to access with facility DT yield-producing region in a non- overAchieving implosion high pressuresshape, in an ICF in shape and can even verge on toroidal igniting ICF implosion) that are oblate implosion requires finessed3,4 control levels of energy, but the struggle to DT fuel test of the stockpile stewardship model. the(see laser Figure power, 2). This and “low-mode” to a lesser extent shape obtain ignition has been an illuminating velocitiescompressibility (several (adiabat), hundreds while of kilometers at the same time obtaining5 very high implosion lasercontrol energy, problem is increased. becomes However,worse as an increase in laser power is the easiest While the road to ignition has been thatper second). can tear apart Obtaining an implosion, high implosion and way to access higher implosion speeds, thatrocky, has recently energized progress researchers has been around made velocities risks introducing instabilities theon NIF world. by our We teamhave achievedand collaborators the highest those instabilities can generate mix that performanceand remember is highermost directly implosion increased. speeds are how an ICF implosion’s fusion to date (i.e., 9.6e15 neutrons equivalent can be quite damaging to an implosion. An alternate way to increase implosion inertial confinement fusion (ICF) yields speed with a given laser power and While it is not the only problem with the National Ignition Campaign (NIC) to 27 kJ of energy), “fuel gain,” and most point design implosion (the “low-foot” excitingly, the first laboratory indications workenergy along is to theseuse a linesmore is efficient presently ablator going performingimplosion), itas appears desired thatfor the ablator-DT higher like high-density16,17 carbon (HDC), and pathof the to key ignition. fusion process called “self- forward. Colleagues at Los Alamos mix was a major contributor6-8 to it not heating” which is a critical step on the velocity NIC implosions. A fusion plasma ignites when the 9-11 18,19 Recently, National Laboratory (LANL) are leading exceeds the rate at which energy is testinga “high-foot” a high-performance implosion has implosion been theAnother beryllium avenue (Be) to higherablator fusion effort. lostpower from produced the fusing by regionthe fusing due region to x-ray developed with the specific goals of radiation processes and heat conduction has lessthat convergence,is more robust and against is generally ablation-front 12less performance in the high-foot is to back Rayleigh-Taylor (A-RT) instability, off somewhat on the DT fuel stiffness processes—aVolume 4 | Numberstate that 2 has| June yet to2014 have (adiabat) generatedStockpile by Stewardship the strength Quarterly of 9

30

25

20

15 (atm-s) [a-off]

t 10 P

performing high-foot implosions is Figureshown 2.in Hot-spottime-integrated shape for x-ray two imaging. high 5 Image spatial units are in microns. Shot

N131119 (NIF year-month-day format 0 1 2 3 4 5 6 7 NYYMMDD) was the highest performing DT shot in a gold hohlraum obtaining Tion (keV) [a-off] total DT yield of 6.1e15 neutrons while shot N140120 was designed to have the samedepleted-uranium implosion speed hohlraum and bang-time isolating of N131119 but was performed in a Figure 1. Lawson criteria (DT plasma pressure x confinement time in atmospheres x seconds) is plotted against inferred ion temperature (in kiloelectron volts). The data are the effect of improved shape. N140120 DT experiments on NIF for low-foot NIC implosions (CH LF, in blue), high-foot implosions obtained a total DT yield of 9.3e15 (CH HF, in green), and high-density carbon 2-shock implosion (HDC, in yellow). The neutrons (not shown, shot N140304 contours show the degree of yield increase due to alpha-particle self-heating. The high- yieldedof the high 9.6e15 energy DT high-footneutrons). shots. The shape foot implosions essentially have closed half the “distance” between the NIC implosions ofClearly, N131119 the depleted-uranium was characteristic hohlraum of many and ignition—the grey region on the upper right. (Data plot courtesy of P. Patel of LLNL). was effective at improving the hot-spot Acknowledgments shape. (X-ray image analysis courtesy 20 the high-foot’s first shock—the trade-off of N. Izumi, S. Khan, T. Ma, A. Pak, L.R. that was made to obtain the improved The results presented in this article Benedetti, R. Town, and D. Bradley of the high-foot stability. This “medium-foot” Weaponswere made and possible Complex through Integration the efforts and NIF Shape working group.) implosionor “adiabat and shaping” the high-foot tactic seeks implosion, an of a large number of people from the optimum between the low-foot NIC

NIF directorates at LLNL, LANL, General 4the National Ignition Facility, Physics of but it will be a matter of research to see Atomics, the University of Rochester Plasmas 21, 056313, 2014. if a tolerable amount of A-RT instability Imploding Capsules at the National Ignition CommissariatLaboratory for à Laser l’énergie Energetics, atomique et R. Rygg et al., “2D X-ray Radiography of with higher DT fuel compressions can auxMassachusetts énergies alternatives Institute of Technology, actually be achieved on the NIF. 5Facility,” submitted to Physical Review (France), and Letters, 2014. With the benefit of a working and Atomic Weapons Establishment (United D.A. Callahan et al., “The Velocity Campaign werepeatable can explore implosion, different effectively directions the in Kingdom).References for Ignition on NIF,” Physics of Plasmas 19, high-foot is a “base camp” from which 6 1 056305, 2012. the high-foot design as we press it to higherparameter performance. space. The In desire doing is so, to weevolve ProceedingsJ.D. Lawson, of “Some the Physical Criteria Society for a Power M.J. Edwards et al., “Progress Towards Ignition on the National Ignition Facility.” will explore failure cliffs that test our Producing Thermonuclear Reactor,” 7 Physics of Plasmas 20, 070501, 2013. designer judgment and the veracity of High-Velocity, Highly Compressed Inertial (London), 70, 6-10, 1957. 2 T. Ma et al., “Onset of Hydrodynamic Mix in experience for those entrusted with the R. Betti et al., “Thermonuclear Ignition Confinement Fusion Implosions, Physical stewardshipour simulation mission, predictions. especially This foris a the key in Inertial Confinement Fusion and 8 Comparison with Magnetic Confinement,” Review Letters 111, 085004, 2013. generation without any underground Physics of Plasmas 17, 058102, 2010. test experience. 3 S.P. Regan et al., “Hot-spot Mix in Ignition- R.P.J. Town et al., “Dynamic Symmetry Scale Inertial Confinement Fusion Targets,” of Indirectly Driven I.C.F. Capsules on Physical Review Letters 111, 045001, 2013.

Office of Research, Development, Test, and Evaluation Volume 4 | Number 2 | June 2014 10

9 17 Capsule Experiments on the National T.R. Dittrich et al., “Design of a High-foot/ Hydrodynamic Instability Growth in S. Ross et al., “High-density Carbon High-adiabat ICF Capsule for the National Inertial Confinement Fusion Capsules at Ignition10 Facility,” Physical Review Letters the National Ignition Facility,” submitted 14 18Ignition Facility,” submitted to Physical 112, 055002, 2014. to Physics of Plasmas, 2014. Review Letters, 2014. ExperimentsH.-S., Park et on al., the “High-adiabat, National Ignition High-foot, ImplosionsD. Casey etat al.,the “Reduced National InstabilityIgnition A.N. Simakov et al., “Optimized Beryillium Inertial Confinement Fusion Implosion Growth with High Adiabat (“high-foot”) Target Design for Indirectly Driven Inertial Confinement Fusion Experiments on Facility,”11 Physical Review Letters, 112, Facility,” submitted to Physical Review 19the National Ignition Facility,” Physics of 15 055001, 2014. Letters, 2014. Plasmas 21, 022701, 2014. O.A. Hurricane et al., “Fuel Gain Exceeding S.A. Yi et al., “Hydrodynamic Instabilities Unity in an Inertially Confined Fusion O.A. Hurricane et al., “The Implosion in Beryillium Targets for the National Campaign on the National Ignition Facility, Implosion,” Nature 506, 343-348, 2014. 16 Ignition Facility,” submitted to Physics of 12 Physics of Plasmas 21, 056314, 2014. PlasmasR. Betti 5, et 1446-1454, al., “Rayleigh-Taylor 1998. Instability Plasmas, 2014. 20 in Inertial Confinement Fusion,” Physics of A.J. Mackinnon et al., “High-Density T. Ma et al., “Imaging of High-energy X-ray 13 Carbon Ablator Experiments on the Emission from Cryogenic Thermonuclear ● K. Raman et al., “An In-flight National Ignition Facility,” Physics of Fuel Implosions on the NIF,” Review of Radiography Platform to Measure Plasmas 21, 056318, 2014. Scientific Instruments 83, 10E115, 2012.

Polar-drive Implosions—Results from OMEGA and the National Ignition Facility by P.B. Radha, M. Hohenberger, F.J. Marshall, R.S. Craxton, D.H. Edgell, D.H. Froula, V.N. Goncharov, J.A. Marozas, R.L. McCrory, P.W. McKenty, D.D. Meyerhofer, D.T. Michel, J.F. Myatt, T.C. Sangster, W. Seka, and S. Skupsky (Laboratory for Laser Energetics, University of Rochester) (a) (b) Spherical Contoured shell Results from polar-drive experiments OMEGA PD (a) 60661 (b) 67345 on OMEGA and the National Ignition NIF configuration configuration gions Spherical Contoured shell (a) (b) Ring 1 60661 67345 Facility (NIF) are described. These Ring 2 Ring 1 Ring 2

Ring 4 gions experiments elucidate the physics of Ring 3 Ring 3 m re 400- µ m re direct-drive implosions irradiated by a µ laser configured for x-ray drive. Implosion 400- velocity, symmetry, and adiabat are 400-µm regions important hydrodynamic parameters for Ring 1 400-µm regions inertial confinement fusion implosions. Ring 2 (c) 58.8˚ ∆r Ring 3 (c) Symmetry in OMEGA polar-drive 42.0˚ experiments can be controlled by beam 20 (c) 21.4˚ 20 Contoured shell repointing and contouring the target SphericalContoured shellshell locally near the equator. NIF implosions 10 Spherical shell 10 are used to identify the effect of laser– plasma interactions on hydrodynamic TC7194J1 0 0 parameters. Measured velocities on the NIF are ~8% lower than those in Mode amplitude (%) Mode amplitude (%) –10–10 simulations that include the effect of Figure 1. Beam configuration for (a) the 2 2 4 4 66 8100 mode cross-beam energy transfer (CBET). NIFtoward and the (b) equator. OMEGA. (c) Schematic of TC10145J1 mode Simulations indicate that symmetry is beams repointing from higher latitudes TC10145J1 influenced by CBET; implosions become more oblate when a CBET model is included in the simulations in agreement As with spherical direct drive, target Figurerepointing 2. Backlit to improve images symmetry from an andOMEGA implosion: (a) employing only beam with observations. implosionincidence ofperformance the repointed is characterized beams. (b) employing shell contouring to improve uniformity. Introduction both beam repointing and imploding shell, the implosion velocity convergence ratio shown on the left for 1 by the peak velocity attained by the Vimp a the(c) Modaltwo cases. decomposition at the to conduct direct-drive–implosion the ratio of the shell pressure to the experimentsPolar drive (PD) at laser makes facilities it possible like , and the adiabat (defined as physics. at Lawrence Livermore National isFermi-degenerate multidimensional. pressure It is important at peak 3–6 the National Ignition Facility (NIF) toshell drive density). the implosions The challenge with adequateis that PD eliminated Infrom PD drivinggeometry, the 20 target of the to 60 symmetry while achieving the desired OMEGA beams nearest the equator are Laboratory that are configured for x-ray Vimp and a. aredrive. repointed To achieve toward nearly the spherical equator. drive,Higher emulate the NIF geometry (see Figure 1). beams closer to the poles of the target Experiments on the OMEGA laser and The polar beams are repointed to the 2 equator (see Figure 1c). A subset of the energies for the beams near the equator remaining 20 beams is used to create compensate for the oblique angle of the NIF are used to study implosion Volume 4 | Number 2 | June 2014 x-rays that backlightStockpile the Stewardship imploding Quarterly 11

200 N130128 8 were post-processed with the x-ray Velocities 4 Prolate were extracted from the13 radius in Data (N130128) tracking code Spect3D. (%) 0 Simulation without CBETthese images, similar to the measured 100 2 Simulation with CBET

P Oblate

locity ( µ m/ns) –4 8 accounts for approximately half of the Ablation surface ve Time –8 4 reductionimages. As in Figure the velocity 3 indicates, measured CBET Prolate 0 450 850 Data (N130128)

400 600 800 1000 (%) 0 Simulation without CBET 2 R µm Simulation with CBET

P Oblate Radius (µm) TC11197J1 TC11072J1 –4 relative to collisional absorption. –8 Further improvements to the CBET experimentally450 inferred850 P Legendre emission, gated x-ray framing camera R µm model in DRACO, particularly in the Figure 3. Inferred velocity from self- FigureTC11197J1 4. Comparison of the simulations with only collisional2 techniques to obtain convergence in the mode for N130128 (symbols) to DRACO energy transfer between beams in the images from experiment (symbols) CBET model, may improve agreement comparedsimulation to that a DRACO also includes simulation the effects with simulations that also include the effect hypothesis is the decoupling of the only collisional absorption (black) and a absorption (black) and DRACO with experiment. Another plausible from either nonuniformity or preheat of CBET (red). CBET (red). ablation surface from the shell resulting plastic shell. With relatively low velocities, the3 implosions do not scale to from the corona. To investigate this, shell.Further Here, improvement a functional in form symmetry for the performed.backlit implosions (where the fuel–shell to test modeling and devise ways to contouringhas been obtained was chosen by contouring where nearly the interface position is tracked) will be improvehot-spot symmetry.ignition, but provide a platform mm of the CH was removed from the 14 indicate that most 2 Preliminary simulations with the CBET equator, while the region below the polar model in DRACO Laser–plasma interactions (LPIs) angle of ~30° was left untouched. Beam11 of the loss from CBET occurs over the processescan reduce such the implosionas simulated velocity Brillouin by driven relative to the pole, resulting pointing was optimized using the 2D equator. This equator is thus under reducing absorbed7 energy through in an overall reduction in velocity and scattering, radiation–hydrodynamics code DRACO. 8 Significantly improved symmetry was cross-beam energy transfer through preheat from energetic obtained at approximately the same (CBET), etc., and increase the adiabat improved symmetry is seen across all the an oblate imploding shell. Figure 4 convergence as shown in Figure 2c. This compares the nonuniformity between decay9 simulation and experiment. The deleteriouselectrons caused effects by of two-plasmonLPI typically NIFLegendre Results modes resolved by experiment. inclusion of CBET in the simulation increase or with radiation increasing in the coronal corona. density The which is in good agreement with results in a more-oblate implosion, scale lengths. Since longer-density primarily designed to study the effect scale lengths are characteristic of the ofImplosion LPI on hydrodynamicexperiments on parameters. the NIF are6 observations.Conclusions to OMEGA, experiments examining High-compression experiments are Polar-drive-implosion experiments thedirect-drive effect of LPIcorona on hydrodynamic on the NIF compared parameters are critical to gaining precluded because existing indirect- on OMEGA and the NIF have been useddrive tophase identify plates and and mitigate beam smoothingthe effect whendescribed. a contoured Excellent shell symmetry was imploded and the confidenceOMEGA Results in implosion modeling. ofare LPI used. on Thesehydrodynamic implosions parameters can be predicted areal density were obtained mm-thick and to demonstrate techniques to PD implosions with indirect-drive improve uniformity through symmetry on OMEGA. Room-temperature NIF deuteriumRoom-temperature are imploded 27- with a variety plastic (CH) shells filled with 10 atm of (a room-temperature implosions phase plates and the existing NIF beam 3,4,6 areand performedreduction ofwith imprint. a pulse Low-adiabat shape that smoothing suggest slower shells by ~8% densities,of pulse shapes measured and varyingthrough adiabats. the has~ a 3),low-intensity foot rising to a relative to the DRACO simulations that energyNearly one-dimensionalloss of secondary (1D) protons, areal10 are include the effect of CBET. The velocity 4 are defocused to improve the on-target, measurement will be verified with flattop pulse shape. The phase plates backlighting measurements in upcoming obtained. Shell shapes are inferred by measured through gated x-ray self- NIF experiments. Symmetry can be Beamfitting repointingthe peak absorption is used to invary the the backlit 3 emissionlow-mode images. symmetry. Simulations The trajectory indicate is controlled in these experiments by images obtained using a Ti backlighter. that the steepest 12gradient in these thevarying change the inpointing phase ofand the beam ℓ energies. images tracks a location close to the Symmetry is well modeled with DRACO; implosion shapes. The best symmetry = 2 Legendre obtained with only pointing variations mode is reproduced by the model. ℓis = shown 4 Legendre in Figure mode 2a dominates when the shell the has ablation surface of the imploding shell. Improving hydrodynamic efficiency by converged by a factor of ~6. A residual Figure 3 shows the inferred velocity using alternate ablators and mitigating versus this radius. DRACO simulations CBET through wavelength detuning will asymmetry at this radius (see Figure 2b). with and without the CBET effect be examined in future experiments. Office of Research, Development, Test, and Evaluation Volume 4 | Number 2 | June 2014 12

References 5 10 1S. Skupsky et al., Physics of Plasmas 11, 6J.A. Marozas et al., Physics of Plasmas 13, 11F.H. Séguin et al., Physics of Plasmas 9, 056311, 2006. 2725, 2002.

2763, 2004. 7P.B. Radha et al., Physics of Plasmas 19, P.B. Radha et al., Physics of Plasmas 12, 2 082704, 2012. 032702, 2005. T.R. Boehly et al., Optics Communications 12 133, 495, 1997. 8W. Seka et al., Physical Review Letters 89, D.T. Michel et al., Rev. Sci. Instrum. 83, 3 175002, 2002. 10E530, 2012. 13 4F.J. Marshall et al., Physical Review Letters 102, 185004, 2009. 9C.J. Randall, J. R. Albritton, and J. J. 14J.J. MacFarlane et al., High Energy Density Thomson, Phys. Fluids 24, 1474, 1981. Phys. 3, 181, 2007. P.B. Radha et al., Physics of Plasmas 20, ● J.A. Marozas and T. J. B. Collins, Bulletin of 056306, 2013. A.Simon, R. W. Short, E. A. Williams, and T. Dewandre, Phys. Fluids 26, 3107, 1983. the American Phys. Soc. 57, 344, 2012.

Highlights and Awards

Upcoming Funding Opportunity His work on the Z machine is focused on University of New York, has received Announcements understanding the high-pressure

the 2014 Young Leaders Professional The Stewardship Science Academic participatedbehavior of noble in the gases Stewardship cryogenically Science ProfessorDevelopment Zurek Award was presentedof The Minerals, with the Alliances Funding Opportunity cooled to an initial liquid state. Root Metals and Materials Society (TMS). Announcement (FOA) is currently recently in San Diego, California. Zurek’s scheduled to be posted on the Academic Alliances program from 2002 researchaward at focusesthe TMS on Annual the use meeting of quantum held ofGrants.gov Properties website of Materials in July. Under This FOA Extreme will 2014to 2007. DOE Early Career Research chemical techniques to explore the Conditionsbe for grants and/or only in Hydrodynamics, the research areas Low Program Award electronic structures of molecules and Energy Nuclear Science, and Stephanie Hansen of Sandia solids. In her work as part of CDAC, she uses an evolutionary algorithm method Researcher to predict the structures of materials Radiochemistry. ProgramNational Laboratoriesaward from the received Department a $2.5 at very high pressures. Professor Zurek million five-year Early Career Research Also in July, an FOA for the High Energy ● Density Laboratory Plasmas grant program is a joint effort with DOE’s of Energy Office of Science. Hansen’s joined the CDAC program in 2013. program is scheduled to be posted. This winning submission, entitled “Non- approachEquilibrium to improveAtomic Physics simulation in High tools Office of Fusion Energy Sciences and Contact Us usedEnergy to Densitydesign high-energy Material,” describes experiments an NNSA’s Office of Inertial Confinement in dense hot plasmas, as well as the Fusion. The specific areas of interest are What do you HED Hydrodynamics, diagnostic tools used to interpret data think about as follows: from them. this issue of • Material Properties, the Stockpile • MagnetizedRadiation-Dominated HED Plasma Dynamics Physics, and Bessel Award Recipient Stewardship Nonlinear Optics of Plasmas and Professor Steven Jacobsen, a Carnegie- • Laser-Plasma Interactions, DOE Alliance Center Academic Partner Quarterly ? We want • from Northwestern University, received to know. Please send Intense Beam Physics, your comments and • Relativistic HED Plasmas and Warm Dense Matter, a 2014 Friedrich Wilhelm Bessel suggestions for future High-Z, Multiply Ionized HED thisResearch award Award. allows Granted the recipient by the to • issues to Terri Stone at Atomic Physics, and spendAlexander a year von working Humbolt at Foundation,a research [email protected]. • gov. Requests to be Plasmas. spend the coming year at the Bayeriches • Diagnostics for HED Laboratory Geoinstitutinstitution in in Germany. Bayreuth, Jacobsen Germany, will where added to our mailing list Former Academic Alliances Program should include your full Graduate Receives 2014 PECASE name, email address, and he was a Humboldt Postdoctoral Fellow Seth Root of Sandia National 2014from 2002 Young to 2004. Leaders Professional affiliation/organization. Presidential Early Career Award for Development Award ScienceLaboratories and Engineering received a 2014 on April 14. Professor Eva Zurek, a Carnegie-DOE Alliance Center Academic Partner research in condensed matter physics. from the University at Buffalo, State Root was selected for his leading edge

Volume 4 | Number 2 | June 2014 Stockpile Stewardship Quarterly