Strategic Research at Los Alamos

Rajan Gupta and David E. Watkins

os Alamos National Laboratory from a broad base of scientific expert- The fullest utilization by the Army of is a scientific institution whose ise and develop effective responses in a the civilian resources of the nation Lprimary mission is to be a timely fashion. cannot be procured by prescribing the steward of the nation’s nuclear deter- Unlike many research environ- military characteristics and require- rent. In a broader context, the ments, ours must balance the freedom ments of certain types of equipment. Laboratory’s mission is to preserve to explore new ideas with a strong Scientists and industrialists are more the security and safety of the United communal commitment to meeting likely to make new and unsuspected States against present and future national security challenges and to contributions to the development of threats. To anticipate future threats making sacrifices when necessary. the Army if detailed directions are and develop the necessary ideas and This balance requires the presence of held to a minimum . . . .” This kind of technologies to detect, foil, and miti- scientific leaders who can inspire oth- thinking is reflected again in the gate possible attacks, we must be ers to contribute innovative ideas and Atomic Energy Act of 1954: “The working at the cutting edge of who can lead the integration of those commission is directed to exercise its research in many branches of engi- ideas into practical solutions. Not only powers in such manner as to insure the neering and science, and we must must we divide our efforts between continued conduct of research and simultaneously integrate a wide range basic research and applied research development and training activities in of research advances from academia and development activities, but we the fields specified . . . .” and industry. must also recognize and seek out syn- Currently, within the Department The long-term success of any scien- ergistic research opportunities in of Energy (DOE) structure, the tific organization is tied to its ability to which progress in one field yields Laboratory-Directed Research and recruit and retain exceptional people greater understanding in another. Development (LDRD) program pro- and to foster collaboration and mean- Finally, there must be a deep recogni- vides resources for discretionary ingful relationships with the finest tion that the evolution of ideas is research. Although this particular for- institutions worldwide. In addition, at rarely predictable and that the Lab mal structure is young compared with Los Alamos and other mission-oriented must position itself to encourage the the 60-year history of the Lab, the ori- laboratories, an environment must be creation and exploitation of new ideas gins of the program go back to the maintained in which the creativity of to meet future challenges. beginning of the weapons program. the staff is readily tapped in order to After World War II, key decision Indeed, some have argued that the ini- implement those missions. Sustaining makers recognized the value of pro- tial work on spherical implosion rep- that kind of environment is a formidable viding scientific organizations with the resents the first LDRD-like effort at task. It has been made more complicated flexibility necessary to pursue innova- Los Alamos. In late April 1943, Seth because emerging threats—global ter- tive ideas. While serving as Army Neddermeyer proposed that a three- rorism, nuclear proliferation, poverty, chief of staff, General Eisenhower dimensional implosion would be a disease, diminishing fossil-fuel and wrote, “Scientists and industrialists potentially more effective means of water resources, stressed ecosystems— must be given the greatest possible assembling a supercritical mass than require that the Laboratory respond freedom to carry out their research. the one-dimensional “gun assembly,”

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which was the baseline design con- cept. Neddermeyer’s concept was ini- tially considered unnecessary and Resolving the Solar Neutrino Problem outside the mainstream of work. Andrew Hime Although the spontaneous rate of plutonium-239 fission is twice that of Since the seminal discovery of the neutrino by Los Alamos researchers Clyde uranium-235, the difference did not Cowan and Fred Reines in the late 1950s, there has been a continuous effort appear to warrant a different design. by Laboratory scientists to study neutrinos and their interactions. Central to Nevertheless, Oppenheimer decided that study is the question of whether the different neutrino flavors—electron, to fund the work on spherical implo- muon, and tau—have mass, a question that has been answered decisively sion to keep the option open. It was with recent data from the Sudbury Neutrino Observatory (SNO). not until the data came in on the reactor-produced plutonium, which SNO was built to resolve the long-standing solar neutrino problem, wherein contained enough plutonium-240 to the measured flux of solar neutrinos reaching Earth is significantly lower than significantly increase the spontaneous predicted. But all previous experiments had been sensitive to only electron neutrinos. Whereas those are the only fission rate, that the work on spherical neutrinos that can be created by the (a) implosion carried out by nuclear fusion reactions powering the Neddermeyer and Kistiakowsky was Sun, the other flavors can be “produced” recognized as essential. Today, the if neutrinos have mass. Through the flexibility afforded through the LDRD process of flavor mixing, massive elec- program continues to provide the tron neutrinos from the Sun can “trans- nation with science and technology form” into muon and tau neutrinos as critical to our defense and security. they travel to Earth. This process would The synergy between the nuclear explain why the measured solar electron weapons program and basic science is neutrino flux is lower than predicted by exemplified by the work of Nobel the standard solar model. Laureate Fred Reines. During the war, A multinational decade-long effort, SNO Reines worked on many different was designed to detect all neutrino aspects of nuclear weapons design. (b) 8 flavors. Los Alamos was involved in SNO SNO

) φ φ After the war, he became an expert on ES CC all aspects of the project, including –1 7 s nuclear weapons effects and played a detector construction, commissioning, –2 6 cm lead role in nuclear weapons testing. simulation, and calibration, as well as 6 5 SNO SSM

(10 φ Toward 1948, Reines wanted to return data analysis and scientific manage- 4 φ τ NC NC ment. The primary detector contains ν , to basic science. Carson Mark, his

µ 3 division director actively encouraged 1000 tonnes of ultrapure heavy water ν 2 this transition and gave Reines the in a large “bottle,” shown in (a). The 1 freedom to “sit and think.” This he did deuterium in the water can interact Flux of with high-energy electron neutrinos 0 for almost a year, during which time 031 2564 through charged-current (CC) weak Flux of ν (106 cm–2 s –1) he decided to search for the elusive e ν → – interactions and with all neutrino fla- CC: e + d p + p + e – 1.44 MeV neutrino, a neutral particle with little ν → ν vors through neutral-current (NC) NC: x + d p + n + x – 2.22 MeV ν – → ν – or no mass, whose existence was pos- weak interactions. All neutrino fla- ES: x + e x + e tulated on the basis of the fundamen- vors also undergo elastic scattering tal principle of energy conservation. If (ES) with electrons, but the reaction is sensitive mostly to electron neutrinos. theory was correct, this particle By enabling a direct comparison of the CC, NC, and ES reaction rates, SNO should be produced in copious quanti- could determine if the neutrinos from the Sun are a mix of electron, muon, ties during a nuclear explosion. and tau neutrinos. As seen in (b), the best fit to the data (dotted circles are Under the nurturing eye of Carson confidence limits) indicates that two-thirds of the electron neutrinos born in Φ SSM Mark, Fred pulled together his vast the Sun transform into muon and/or tau neutrinos. ( NC is the NC flux pre- dicted by the standard solar model.) Together with data from other experi- experience with detection of different ments, these results demonstrate that flavor mixing almost certainly resolves forms of radiation, his abilities to do the solar neutrino problem and that neutrinos have mass. Moreover, the total big science, and the technical capabil- flux of neutrinos measured at SNO agrees with predictions and our basic ities of Los Alamos to build a detector knowledge of how the Sun shines. Continued on page 204

Number 28 2003 Los Alamos Science 201 Strategic Research at Los Alamos

A New Source of Ultracold Neutrons

Chen-Yu Liu, Steve K. Lamoreaux, Thomas J. Bowles, and Christopher Morris

A neutron will normally diffuse right through materials We have recently conducted experiments to under- such as steel or lead, but if the neutron’s energy is stand and characterize the performance of solid deu- exceedingly low, it will instead be reflected by those terium as a so-called superthermal UCN source. As (or other) materials. We can now produce neutrons with seen in graphic (a), a pulse of high-energy protons kinetic energies less than about 300 nano–electron from the Los Alamos Neutron Science Center is volts. When placed in a “bottle” directed to a tungsten target that of the right material, these ultra- (a) sits inside a liquid nitrogen dewar. cold neutrons (UCNs) become B Valves A High-energy spallation neutrons trapped, enabling us to collect exit the target, lose most of their them and to make a high-density To experiment energy in a layer of polyethylene, UCN source. and enter the liquid helium dewar 58 Ni coated that holds the solid deuterium. A stainless guide Such a source can offer orders- neutron can collide with a deuterium of-magnitude improvements to molecule and resonantly transfer experiments that make precise Liquid N2 essentially all of its kinetic energy measurements of neutron prop- Be reflector to the deuterium lattice. By this erties. For example, Los Alamos superthermal process, a relatively LHe is vigorously pursuing an exper- large fraction of the incoming iment to measure the angular Solid D2 neutrons become ultracold. They correlation between a neutron’s Polyethylene then diffuse to the UCN bottle spin and the momentum of the region, where the sequenced clos- electron that emerges when the Tungsten target ing of valves B and A trap them. neutron decays. The experiment Proton beam should provide a precise meas- We have demonstrated a proto- ure of the ratio of the vector and type, solid deuterium source, axial-vector coupling constants shown in (b), that produced about in the electroweak interaction in (b) 120 UCNs per cubic centimeter the Standard Model, and so can inside the bottle region, a much be used to test the unitarity of higher value than can be provided the CKM matrix (the matrix by other facilities. A source with that rotates the complete set of potentially six to seven times that quark mass states into the com- UCN density is being engineered plete set of quark weak states). for the angular correlation experi- Another experiment aims at ment mentioned above. We are improving the limit set on the also investigating solid oxygen as as-yet-unobserved neutron elec- a candidate for the next generation tric dipole moment (EDM), the superthermal UCN source. Our existence of which would vio- preliminary calculations indicate late parity and time reversal that this new material might yield symmetry. The neutron EDM, a UCN flux output 250 times therefore, serves as a critical test greater than than that achieved of fundamental particle theories with solid deuterium. that are extensions to the Standard Model.

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The National High Magnetic Field Laboratory—A User Facility

Alex H. Lacerda and Gregory S. Boebinger

(a) The National High Magnetic Field magnetoresistance measurements, or Laboratory (NHMFL) at Los pulse-echo ultrasound and gigahertz Alamos has emerged as one of the spectroscopies. leading pulsed-magnetic-field research centers in the world, When energized at peak fields, the hosting an international user pro- different magnets have magnetic gram that attracts around 150 vis- energies between 0.5 and 100 mega- iting scientists a year to Los joules. As a megajoule is roughly the Alamos. Part of the NHMFL con- energy equivalent of two sticks of sortium (which has other facilities dynamite, research involving high at Florida State University and the magnetic fields is, in part, an exer- University of Florida and is joint- cise in applied metal fatigue. With ly funded by the National Science (b) pressures in the magnets approaching Foundation, the State of Florida, 1.4 gigapascals (200,000 pounds per and the Department of Energy), square inch), not only does copper the NHMFL–Los Alamos is a wire stretch and rupture, but even multipurpose facility, powered not garden-variety steels fracture cata- only by a 1.4-billion volt-amperes strophically. To combat the metal power generator (the country’s fatigue, the Los Alamos engineers largest) shown in (a) but also by and metallurgists working with the the intellectual energy of its per- NHMFL have helped to develop a sonnel and user community. variety of nanostructured conductors and exotic reinforcing materials with In (b), researchers are shown greatly enhanced mechanical examining data that come from strength. magnets in cells 3 and 4 of the facility, each of which contains a The technical expertise needed to 60-tesla “short-pulse” magnet that (c) maintain the NHMFL magnets is an provides a 25-millisecond mag- asset, and it is frequently applied to netic pulse. These magnets are the problems involving pulsed-power, workhorses of the NHMFL user electromagnetic modeling, and other program and are used for magne- projects that serve the Laboratory’s totransport, magnetization, and broader mission. The pulsed magnets radio-frequency conductivity themselves provide a unique scientif- experiments. Researchers in the ic platform for developing and test- background are clustered around ing experimental techniques in a cell 2, which contains a 50-tesla readily reproducible transient envi- “midpulse” magnet, shown in (c), ronment. Finally, NHMFL scientists that is primarily used for optics actively collaborate with other Los experiments, such as photolumi- Alamos researchers on fundamentally nescence. Another frequently used important missions ranging from magnet is the “large-bore” 50- nanoscience to plutonium. tesla magnet that is used for measurements requiring some “elbow room,” such as angle- dependent magnetization and

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Continued from page 201 that would “see” the neutrino. In 1956, Reines and his team discovered the neutrino using the Savannah River EpiSims nuclear reactor as the neutrino source. That work opened up the field of Stephen Eubank experimental neutrino physics, which is still actively pursued at Los EpiSims is a novel software system for simulating the spread of disease in a Alamos. Recently, Laboratory scien- large urban population. It is built upon the very detailed models of population tists played a leading role in an inter- mobility provided by UPMoST (Urban Population Mobility Simulation Technology), a simulation system that was also developed at Los Alamos. national collaboration that presented UPMoST fuses informa- (a) the first evidence that neutrinos oscil- tion from different types late from one type to another. Such of data, such as local cen- conversion of electron-type to muon- sus data, household activi- type neutrinos is now believed to ty data, transportation solve the solar neutrino riddle— data, and others and uses explaining why the number of elec- them to build a synthetic tron neutrinos detected at the earth’s population of individuals surface is far smaller than the number who move about an urban region in a realistic net- that solar models predict (see the box work of contact patterns. “Resolving the Solar Neutrino EpiSims takes this model Problem” on the previous page). of population mobility and To highlight how ideas in science adds to it models for how (b) and technology merge into major pro- disease is transmitted from grams, we look back to biological person to person or con- research in the 1960s. The principle of tracted from contaminated flow cytometry—a flow method in environments. which cells are rapidly interrogated These graphics show the one cell at a time—was invented progression of a smallpox through Laboratory-directed research, epidemic as estimated by and the first device was reported by an EpiSims simulation. The Mack Fulwyler in 1965 in Science virus was released among (Volume 150). A few years later, Los students at a university in Alamos flow cytometers could sort downtown Portland, (c) cells by DNA content, enabling scien- Oregon. Six hours after tists to study the effects of exposure to having been exposed, the radiation or to carcinogenic chemi- infected people—see graphic (a)—have quickly cals, issues relevant to worker safety spread through the down- within the DOE. By 1985, the town area. The height of Laboratory and Lawrence Livermore each bar indicates the num- National Laboratory were sorting the ber of infected people at different chromosomes in the human each location. Graphic (b) genome with 95 percent accuracy and shows that, after 40 days, supplying libraries of cloned frag- and without a mitigation ments for each chromosome to molec- strategy, the virus has ular biologists around the world. In spread throughout the city. The simulation shows that the contagion has touched many demographic groups, so any strategy designed to mitigate the effects of the meantime, George Bell, a theoreti- the contagion must accurately take this demographic mixing into account. cal physicist formerly in the nuclear Graphic (c) shows the viral progression 40 days after the initial infection, but it weapons program, had founded a includes a mitigation strategy that targeted those people who came into contact unique group in theoretical immunol- with contagious people. People who showed symptoms of smallpox were isolat- ogy using LDRD funds. George ed, and their contacts were vaccinated starting 14 days after the attack. encouraged his longtime collaborator

Continued on page 206

204 Los Alamos Science Number 28 2003 Strategic Research at Los Alamos

The Magnetized Universe (a)

Hui Li and Stirling A. Colgate

Observations of the cosmos reveal that in the center of most massive galaxies lies a supermassive black hole. These enigmatic objects form by packing 108 solar masses into a region the size of our solar system, and roughly 1062 ergs of gravitational energy are released during the formation process. A part of this energy is ejected from the region of the black hole as a giant jet or outflow. Such an outflow is visible as the collimated luminous emission in (a), which is a color-coded “radio map” of the giant galaxy M87 in the constellation Virgo. It has been a great challenge to understand the formation of these outflows. Furthermore, where the outflow breaks up, we see radio lobes, which are identified as large regions of space filled with mag- netic-field energy and high-energy particles. By studying approximately 100 galaxies with radio lobes, we found that the total energy of the lobes can (b) Electromagnetic be up to 10 percent of the energy released when the black hole formed. The Poynting flux identification of this enormous amount of magnetic energy has, among other Force-free helix things, led us to a model of black-hole formation in which gravitational energy conducting is transformed into magnetic energy by a galactic-scale dynamo. Magnetic medium helix 1 MPc In the early stages of galaxy formation, circulating matter typically forms a disk because of its finite amount of angular momentum. Transporting angular momentum away from the central disk region is essential if the matter is to move inward and collapse to form a supermassive black hole. We have iden- tified a global angular-momentum transport mechanism and performed hydrodynamic simulations to show that large-scale vortices, indicated by col- ors in (b), can efficiently transport angular momentum outwards. The inner portion of the disk is a conducting plasma that completes roughly 1011 revo- lutions during the 108 years it takes for the black hole to form. We propose that a dynamo process will convert that rotational kinetic energy into magnet- ic-field energy. A cut-away view of the inner region is shown in (c). Because of the differential rotation, the disk twists and amplifies a poloidal “seed” magnetic field (with a radial component in the disk) into a toroidal field. Simultaneously, a large number of stars are swarming in and around the disk, Outer and we expect an exceedingly large number of star/disk collisions to occur accretion disk during the period of black-hole formation. Each collision makes a plume (c) that transforms a fraction of the enhanced toroidal field back into the poloidal field. Calculations indicate that this process can lead to a posi- Collision plume Flux expanded Star and rotated into tive dynamo gain, allowing the seed field to be exponentially amplified. Extended toroidal poloidal plane We are conducting a laboratory experiment using liquid sodium to model flux this dynamo process. Poloidal seed field Our calculations also show that the fraction of the poloidal field that extends outside the disk is wrapped up by the disk into a force-free Disk helix, carrying away the energy released by the black-hole formation as Black hole a Poynting flux—see graphic (b). After tens of millions of years, the Rapid helix extends well beyond the galaxy to nearby galaxies. This fact, along Toroidal field reconnection with the observation that supermassive black holes are ubiquitous, led us ~100 A.U. to suggest that a significant fraction of the volume of the universe is filled with magnetic fields. We are still trying to understand how magnetic reconnection can reconfigure those fields and lead to the distorted shapes seen in (a). We are also trying to find out whether our model can lead to the acceleration of the high- energy particles (for example, cosmic rays) and whether, in the ultimate “global warming” scenario, the field heats up the wider intergalactic medium.

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Continued from page 204 Walter Goad to follow his visionary national security. We do not yet know Both these groups of fellows are ideas regarding molecular biology all the long-term implications of selected on the basis of academic and start the first data bank (known quantum information technology. record, research activities and inter- as GenBank in 1983) for the storage However, we have a strong sense that ests, and leadership potential. They and analysis of DNA sequences. continued research in quantum phe- are then supported fully for 2 to Subsequently, one of George’s nomena will play a major role in the 3years to pursue their own research younger collaborators, Charles technological edge and security of the interests, develop a familiarity with Delisi, left Bell’s group for an influ- nation. the Laboratory’s programs, and inves- ential position at DOE, and Delisi These examples of innovation tigate ways in which they can match leveraged those two LDRD-sponsored amply demonstrate that intelligent, their talents with the needs of the initiatives, the DNA libraries and data technically gifted, tenacious people Laboratory. Over time, this program bank, to win DOE sponsorship of the with broad interests create revolutions has proved to be extremely success- nation’s Human Genome Project. The that change society. But how does an ful—a significant fraction of those efforts to understand, at a fundamental institution identify such creative peo- fellows join programs early in their level, how genomes function have had ple, and how long should they be sup- stay at Los Alamos and eventually a direct and continuing impact on our ported to think and explore without become leaders, both as scientists and national security. Throughout the constraint? Should a person whose managers. Furthermore, many of the 1990s and continuing to this day, tech- interests do not match the immediate other outstanding candidates who par- nologies from the Human Genome needs or mission of an institution be ticipate in this competition but are not Project have helped combat the threat supported? selected as “fellows” are hired as pro- of biological warfare agents. Rapid The diversity of past success sto- grammatically funded postdoctoral DNA analysis tools and miniaturized ries tells us that there is no simple research associates. The competition instruments continue to be developed answer, nor is there a cookbook is intense, and the combined pool of and fielded for either military or recipe. The best one can do is to hired candidates, superb. This homeland security applications. assign the task to peers, assuming the approach has ensured the highest As new threats emerge, new areas maxim that it takes one to know one. possible quality of the technical of science crop up to help mitigate The system works provided a suffi- staff recruited through the postdoc- them. A particularly interesting exam- ciently large community exists, whose toral program. On average, there are ple is the application of quantum members, in spite of large egos and a 300 postdoctoral fellows and mechanical principles to information very high degree of competition, value research associates working at the technology. Richard Feynman recog- truth and the quest for truth. For many Laboratory at any one time. Many of nized that processing information years, the Laboratory has used techni- them become part of the permanent using quantum physics would result in cal peer review as its decision mecha- staff. Those who leave Los Alamos significant differences compared with nism when confronted with funding for positions in academia or industry classical physics approaches. Today, discretionary research. That mecha- often continue to contribute to our we are witnessing the emergence of a nism produced high standards in the intellectual vitality through collabora- technology based on quantum past, and the Laboratory will best suc- tions with our staff. mechanical principles that can guaran- ceed in meeting future challenges by Many of those recruits consider tee secure communications. Richard sustaining that tradition. their postdoctoral experience as one Hughes, originally a postdoctoral fel- We will also continue to support of the most productive periods of low in the elementary particles and the Laboratory’s vigorous postdoctor- their lives. As permanent staff, how- field theory group, used LDRD funds al program. It is a superb mechanism ever, they often experience too many to start an experimental effort in quan- for attracting the best young constraints on their productive time. tum cryptography, a technique that researchers to our programs. Each Proposal writing, delivery on pro- exploits the properties of single pho- year, the Laboratory makes a special grammatic milestones, and managing tons to distribute cryptographic keys strategic investment by recruiting business aspects can take too much with guaranteed security against about 25 postdoctoral fellows and 6 time away from creative thinking and unwanted interception. Hughes and distinguished postdoctoral fellows innovative problem solving. The his colleagues made rapid progress through a highly competitive process. Laboratory is working to change this and are now supported by program- The latter group is evenly divided situation. No doubt, from an institu- matic funds. This technology has among the J. Robert Oppenheimer, tional perspective, the Laboratory immediate potential to improve our Feynman, and Reines categories. needs to hire from among the best

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and brightest postdocs and hire those strategic investments. In the article Rajan Gupta graduated from the University of who can work effectively on teams, following this one, for example, Los Delhi in 1975 and obtained his Ph.D. in theo- who see the value of multidiscipli- Alamos scientists discuss how they retical physics from the California Institute of nary approaches to complex prob- are using sophisticated mathematical Technology in 1982. He came to Los Alamos as a lems, and who can contribute to our tools to combat HIV, how they deter- J. Robert Oppenheimer diverse work—from fundamental sci- mined when the virus entered the fellow in 1985 and is ence to pragmatic solutions, and from human population, and how they currently the leader of those to complicated national technol- came to understand the complex battle the Elementary Particles and Field Theory Group. ogy and security needs. But the that rages between the virus and the He is an elected fellow Laboratory also needs to enable these immune system. In another article, of the American young scientists to contribute cre- scientists describe their latest high- Physical Society, and his atively over many decades. The pay- resolution techniques for modeling main areas of research offs from basic science are generally Earth’s oceans. The research promises are in lattice QCD and the phenomenology of the Standard Model, and in computational long term, and basic science results to increase our ability to predict cli- physics. He is also deeply involved with accel- are seldom accomplished without sus- mate change. For the emerging field erating the delivery of education and health tained effort. That effort is possible of nanotechnology, we have devel- care globally and with issues of international only through maintaining a good sup- oped a new type of laser based on security. port infrastructure in all the business nanometer-size bits of matter, paving aspects of the Laboratory and secur- the way for ultraefficient optical ing stable funding for science. devices. Other researchers discuss the David Watkins is a native son, who grew up in New Mexico and obtained a bachelor’s degree in Historically, very smart people Laboratory’s seminal role in fuel cell physics from New Mexico Tech. He first came to willingly sacrificed their self-interests research and development as well as Los Alamos as a graduate student for the sum- and worked collectively on projects our efforts to simulate the flow of mer of 1975, before when they believed in the urgency water into and out of a regional basin. attending the University of Washington, where he and importance of the mission. Two The Laboratory is strongly committed received a Ph.D. in outstanding examples of such projects to supporting an array of activities in physics. He returned to are the Manhattan Project, conducted basic science to sustain its vitality and Los Alamos in 1979 to at a time when eminent scientists meet the long-term challenges of its work on the laser fusion understood the danger posed by Nazi missions. The boxes accompanying program, developing solid-state nonlinear opti- Germany and its allies, and the call this overview highlight but a few such cal technology. David by President John F. Kennedy in 1961 projects undertaken by the Los spent the next ten years to put an American on the moon by Alamos staff. of his career as a technical staff member, work- the end of the decade. Today, we face At this critical juncture in history, ing on various program—from laser isotope sep- aration to Department of Defense programs. a similar challenge in the war on we are rededicating ourselves to the Between 1988 and 1989, David worked at the global terrorism and on poverty, dis- pursuit of excellence in science and Royal Signals and Radar Establishment in ease, and diminishing resources. How technology at Los Alamos. We are Malvern, England, as part of a technical does an institution retain the capabili- also finding new ways to communi- exchange for the Strategic Defense Initiative. ty to respond to such new challenges cate to society at large the essential Upon his return to Los Alamos, he joined the semiconductor physics team in the Electronic after years of working on one mis- nature of our basic and applied and Electrochemical Materials and Devices sion, the stewardship of the nuclear research and give the nation confi- Group. David served as both deputy leader and stockpile? Once again, one comes to dence in the integrity of our science leader for that group. In 1999, on April Fools’ understand and appreciate the sound and technology. Day, David joined the LDRD program office and later became LDRD program manager. judgment and farsightedness of the Laboratory’s founders, who put a pre- mium on strategic investment in skilled and talented people and on creating an environment that rewards and nurtures them. Many of the broad and intercon- nected challenges being addressed by Laboratory scientists are evident in the topics covered in this section on

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