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Lab News -- May 27, 2005

May 27 , 2005

LabNews 05/27/2005PDF (650KB)

Z accelerator pushes aluminum plates faster than Earth moves through space

By Neal Singer

The object, which resembled a small plate, slid smoothly from its launch site. By the time it traveled 1/6 of an inch, it had reached a velocity of 76,000 miles per hour, or 50 times the speed of a rifle bullet. In less than a second, the plate had gained approximately three times the velocity needed to escape Earth’s gravitational field.

No human could survive that enormous acceleration. The plate itself remained intact only because of the smoothly increasing thrust of the huge magnetic field driving it. A single sharp jolt would have vaporized the plate.

The speed of the thrust was a new record for Sandia’s electrically driven Z accelerator, sometimes referred to as the fastest gun in the West. Actually the fastest in the world, it is now able to propel small plates shocklessly at 34 kilometers a second, faster than the velocity Earth travels through space (30 km/sec) in its orbit about the sun.

The point of the achievement, however, is not speed for speed’s sake.

“Being able to send material so fast is not just for vanity or the Guinness Book of Records,” says Marcus Knudson (1646), lead scientist on the effort. “This is presently one of the few ways on earth to get hard information on problems that concern efforts at the outer reaches of science, rather than having to rely on complex speculations that may or may not be correct.”

Says Yogi Gupta, a professor known for his work in shock physics at the Washington State University in Pullman, “If you had asked me a few years ago if we could send something this fast, I would have said you were joking. But mankind is always trying to create conditions in the laboratory that imitate extreme conditions [found elsewhere].”

Data from the new work, made possible by an upgrade in Z’s firing mechanism, will help engineers more optimally design deuterium capsules to achieve peacetime nuclear fusion, an eventual source of low-environmental-impact electrical power. The high-pressure regimes also provide data for stewardship of the nuclear stockpile — data formerly impossible to come by except through a nuclear explosion in underground experiments.

By creating states of matter extremely difficult to achieve on Earth, the flyer plates also provide hard data to astrophysicists speculating on the structure and even the formation of planets like Jupiter and Saturn.

Says Didier Saumon, an astrophysicist at Los Alamos National Laboratory, “The internal structures of Jupiter and Saturn are composed mostly of hydrogen, so knowing its equation of state [how hydrogen and its isotopes behave at pressures from one to 50 million atmospheres] is highly relevant to how we infer the interior properties of these planets. Z gave us hard data.”

The results were reported at the March meeting of the American Physical Society.

The immediate purpose of these very rapid flights is to measure the response of materials at extreme conditions. Z’s hurled plates strike a target after traveling five millimeters. The impact generates a shock wave — in some cases, reaching 15 million times atmospheric pressure — that passes through the target material. The waves are so powerful that they do not merely penetrate or even pulverize the materials. They turn solids into liquids, liquids into gases, and gases into plasmas in the same way that heat melts ice to water or boils water into steam. The difference is that in the heart of the 120-foot-diameter accelerator, the process takes place at far higher temperatures and in much shorter times than the kitchen stove could ever approach. The pressures produce states of materials rarely seen or measured in the laboratory.

The trick in accelerating the fragile, 850-micron-thick aluminum plates at 10 to the 10th Gs (force of Earth’s gravity) without vaporizing them lies in the finer control now achievable of the magnetic field pulse driving the 30 mm by 15 mm fliers.

For Z’s better known effect — vaporizing fine wires at its center to create nuclear fusion — the trick is to get current to travel down Z’s 36 cables as simultaneously as possible, so that all the amperage strikes its target with as short a risetime as possible, approximately 100 nanoseconds.

To send a plate flying instead, the arrival of energy at the target is staggered over 300 nanoseconds, so that the amperage arrives less like a tidal wave surge and more in controllable increments.

This requirement was better achieved by a recent upgrade that removed a single laser formerly used to trigger current in all cables simultaneously. In its place, 36 laser switches were installed — one for each cable. This change permits researchers to shape the electrical pulse that arrives at the target, with a corresponding modulation in the magnetic field driving the plate.

An upgrade of Z planned for next year is expected to achieve plate velocities of 45 to 50 km/sec, says Marcus, driving targeted materials further into their plasma regime.
Z’s former record in propelling plates was 21 km/sec, set two years ago. -- Neal Singer

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Team discovers unsuspected intermediates in the chemistry of combustion

By Nancy Garcia

Combustion Chemistry Dept. 8353 researchers Craig Taatjes, Nils Hansen, Andy McIlroy, Jim Miller, Juan Senosiain, and Stephen Klippenstein are part of an international team that published a Science Express paper May 12 about the surprising detection of a class of compounds previously unknown in flames. This result could have implications for areas as diverse as understanding pollutant formation in combustion and modeling interstellar chemistry.

The discovery of these compounds, called enols, is the biggest breakthrough so far from a powerful new flame chemistry probe, operated at the Advanced Light Source at Lawrence Berkeley National Laboratory (LBNL), that was developed by researchers from Sandia, LBNL, Cornell University, and the University of Massachusetts in late 2002.

This machine, and a similar device operating at the National Synchrotron Radiation Laboratory in Hefei, China, investigate molecules sampled from flames by combining mass spectrometry (to reveal molecular weight) with ionization by vacuum-ultraviolet light emitted from a synchrotron. One key capability of the machines is that they are able to distinguish isomers — molecules made of the same atoms but in different arrangements — that can have very different chemical characteristics. Enols are less-stable isomers of other well-known combustion intermediates.

They were found when the team was looking for signatures of different isomers in flames. With this finding, enols can be added to predictive computer models currently used to improve combustion efficiency and cleanliness.
“It is remarkable that, even after 150 years of flame chemistry research, new compounds can be found in flames,” Craig says. “Enols themselves are chemically interesting; they were predicted to be transient chemical intermediates in 1880, but the first direct observation of the simplest enol, vinyl alcohol, wasn’t until 1973. Although these compounds have been elusive,” he adds, “it turns out they are just sitting in flames.”

The unanticipated detection of enols could also have a significant impact in refining models used to describe fuel cell operation and emission-free waste cleanup using supercritical water oxidation, Craig says. Astronomers have also observed ethenol (one of the enol compounds now identified in flames) in interstellar space. The new enol findings may provide clues as to how complex organic molecules form in interstellar space.

Besides the Sandia scientists, the team that discovered enols in flames includes researchers from Cornell University, the University of Massachusetts, the University of Bielefeld (Germany), and the National Synchrotron Radiation Laboratory in Hefei, China . -- Nancy Garcia

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Pulsed power and making an impact: Pace VanDevender, looking back on three decades, finds Sandia still a great place to work but with evermore complex operational requirements

By Ken Frazier

In the three decades since now-retiring Chief Technology Officer and VP for Science, Technology, and Partnerships Pace VanDevender joined Sandia in 1974, he says the most important things about Sandia are unchanged, but one new thing poses challenges still unresolved.

What’s unchanged, he says, are the Sandia culture, the strong sense of identity Sandians have, and the opportunity to make an impact. What has changed are new layers of operational oversight and regulatory requirements that in effect constitute an entire second new goal for Sandia, operational excellence.

How the mix between “mission excellence” and “operational excellence” turns out is still a bit unclear, but nevertheless, he says, Sandia is still a great place to work.

“Sandia was always a place where you could go to make a difference,” says Pace, who announced in a May 3 letter to the Laboratory Leadership Team that he would leave his current position on June 2 to retire on July 14. He says he joined Sandia as a young physics PhD for two reasons. First, Sandia was where pulsed power was going to be applied to fusion, “which was my mission in life at the time.” The other, he says, was to work where people want to make a difference in the world around them.

Wanting to make a difference

“The engineering culture and mindset of Sandia directly led to everyone wanting to make a difference,” he says. “We call it these days a deliverable; we used to call it an impact.”

Pace became a division supervisor in 1978, manager of the Fusion Department in 1982, and director of Pulsed Power Sciences in 1984, a position he held into the 1990s. Between then and becoming VP in July 2003 he was director of Corporate Communications, the National Industrial Alliance, Strategic Sciences, Integrated Information Services (Chief Information Officer), and Executive Staff. When he interviewed job candidates for roles in these centers, he would ask them what they wanted out of life.

“I’d give them three options: money, freedom, and impact,” he recalls. “If they said money, I’d direct them to business. If they said freedom, I’d direct them to academia. If they said impact, I said, ‘You’re in the right place,’ and we’d continue the interview,” he says.

“That’s actually broadly practiced across Sandia,” he says. “As a result we have a cadre of wonderful people who are dedicated to exceptional service in the national interest, making a difference in the world.”

He recalls that 30 years ago things were done, at least from a pulsed-power point of view, in a much more self-contained way. “We had our tribes,” he says, and they went and did their jobs.

“Even so we still felt we were part of Sandia. This is the only place I know where we call ourselves by a special name — Sandians. You don’t say, ‘There’s a Los Alamos-ite or a Livermorean . . . person — there’s no name for it.

“We have transcended our tribes to have a corporate laboratory ethic and identity. And I’m very, very proud to be a Sandian. It means integrity. It means figuring out what’s right for the country. It means putting the nation ahead of the lab, ahead of the organization, ahead of the individual. That’s recently articulated but it has been long felt. So that’s the kind of thing that has not changed.”

A politically sensitive environment

“What has changed,” he says, “is that we are in an even more politically sensitive environment. And the struggle to find a new relationship with NNSA and DOE is still a tough challenge.

“When we still had a visible, peer-competitor adversary, the Soviet Union, then our value was immediately obvious and well-felt by everyone. Since the end of the Cold War we’ve been in a transition period and our value is not as evident to everyone as it once was.”

He says this loss of perceived value — he emphasizes that this is a misperception, not a loss of value in reality — requires educating others in Washington and elsewhere about what Sandia and the other national labs do. (He adds that competitors will come back eventually and the world is still a dangerous place, in a nuclear sense, and becoming more so.)

But there’s a related change as well.

“I think we are being asked to uphold an operational standard that we didn’t have to uphold before,” Pace says. “So operational excellence has become ‘job one’ as opposed to mission success as job one. The emphasis now is really on operations — environment, safety, health, and security — and fiduciary accountability — all the hows. That’s now job one. That is a big change, and we’ve not yet adapted.”

That may be a bit uncomfortable for Sandians, he notes, but it nevertheless must be done and done correctly — while carrying out our mission.

“It is essential that we learn to work with SSO and NNSA headquarters so we can reach a new standard of regulatory excellence and mission success. We need to pull mission success as a priority back up to be at least on par with regulatory excellence.

A sophisticated strategy required

“Today’s challenge is a far cry from what it was when I came,” Pace says. “It’s always easier to have one goal, and a motivating one. Multiple goals require a more sophisticated strategy.”

Some internal studies have been done on the various functions that take up Sandians’ time. “It’s pretty daunting how much time we spend on nontechnical things,” Pace says, “but it is not crippling.” Research environment surveys conducted in 2001 and 2003 showed increasing frustration in not having uninterrupted time to do the technical work that drives Sandians.

“Although the focus groups that I have held with department managers and senior scientists have identified this problem, this issue, they have always ended with someone admonishing me that this is still a great place to work. In fact the 2001 and 2003 surveys both affirmed that Sandia is a great place to work. And that affirmation is significantly above the norm of the other institutions surveyed. So you have to keep that in perspective. Sandia is still a great place to work.”

After former manager Paul McWhorter left Sandia for private enterprise and decided to stay with his company, Pace went and debriefed him about his decision, “to try to understand what he thought about Sandia.” Pace says Paul told him, “Tell people back at Sandia that Sandia is the last great place on earth for a technical professional to work.”

Pace repeats those words slowly for emphasis. “I think that still is something that Sandians need to keep in mind. And now the rest of Sandia has an obligation to maintain that environment.”

Pace’s highlights of working at Sandia start ultimately with the people. Says he: “Ron Detry [VP 4000] likes to say, and I’d like to quote him: ‘Sandia has only its people and its reputation — everything else is owned by the government.’ ”

E.O. Lawrence Award

A visitor suggested perhaps Pace’s receiving DOE’s E.O. Lawrence Award in 1992 was one highlight. He was only the fifth Sandian to receive the prestigious award. He quickly points out that the Lawrence award is “individually conferred” because that’s the way it is set up, “but I and the 300 other people in pulsed power knew that it was recognition of the excellence of pulsed power at the time. That was a high.”

“The first shot of PBFA I [particle beam fusion accelerator 1, the first of the big pulsed power accelerators of which the Z machine is the current manifestation] was a high. It was on a Saturday morning at work.” He says the crew wanted to immediately repeat the shot but that wasn’t the plan. “I went to see the first Star Wars movie that day, which had just opened, and I looked around and there were probably 15 or 20 Sandians who were there also and still charged up over the morning activities.”

The first shot on PBFA II, on Dec. 11, 1985, was “another great experience.”

“The nice thing about pulsed power is that we are still only at the beginning. The achievements have been miraculous in the last 10 years, and there is still so much more science and engineering that’s going to come from these people. I look forward to cheering them on.

Magnificent acheivements

Pace quickly reels off a host of Sandia contributions. He calls each “a magnificent achievement”: the W88 AF&F and now the W76-1, the MTI satellite, MicroChemLab, decontamination foam, the progress in bio, each launch of the targets for ballistic missile defense, MESA, the Red Storm computer, the SCN [Sandia Classified Network], Oracle, solar-generated hydrogen with nanotechnology — all are examples of Sandia “magnificent achievements,” he says.

“They are real accomplishments by teams of Sandians doing what would seem to be impossible things. It’s a thrill, every one of them. Just reading the Accomplishments publication every year renews the high, so I’ve had the pleasure of tens of highs.”

Will it be hard to leave Sandia? Pace points out that he did it once before. He went on a technology transfer leave of absence for two-and-a-half years, “and found that Sandia did just fine without me and will do so again.”

“So I know what it feels like to terminate from Sandia,” Pace says. “Industrial psychologist Harry Levinson told me, ‘All change is loss and all loss has to be mourned.’ I expect to mourn but it will be a gateway to a new adventure.”

But he quickly adds: “In fact, once you are a Sandian you are always a Sandian, at heart. Sandia will still be here and I will be watching it and cheering it on as I try to do something really different.” -- Ken Frazier

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