From DOE’s Sandia National Laboratories (US) and From DOE’s Lawrence Livermore National Laboratory (US) : “Setting gold and platinum standards where few have gone before”

From DOE’s Sandia National Laboratories (US)

and

From DOE’s Lawrence Livermore National Laboratory (US)

June 24, 2021

Neal Singer
nsinger@sandia.gov
505-977-7255

Extreme pressure at DOE’s Sandia National Laboratories (US) and DOE’s Lawrence Livermore National Laboratories.

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Eight gold samples, four per panel, prior to assembly of the panels into a “stripline” target for Sandia National Laboratories’ Z machine. There they were vaporized by the enormous pressures produced by Z’s 20-million-ampere current pulse. This arrangement will permit four measurements, one for each pair of samples in which one pair is on each panel at the same position Photo: Leo Molina.

Like two superheroes finally joining forces, Sandia National Laboratories’ Z machine — generator of the world’s most powerful electrical pulses [below]— and Lawrence Livermore National Laboratory’s National Ignition Facility [below] — the planet’s most energetic laser source — in a series of 10 experiments have detailed the responses of gold and platinum at pressures so extreme that their atomic structures momentarily distorted like images in a fun-house mirror.

Similar high-pressure changes induced in other settings have produced oddities like hydrogen appearing as a metallic fluid, helium in the form of rain and sodium a transparent metal. But until now there has been no way to accurately calibrate these pressures and responses, the first step to controlling them.

Said Sandia manager Chris Seagle, an author of a technical paper recently published by the journal Science, “Our experiments are designed to measure these distortions in gold and platinum as a function of time. Compression gives us a measurement of pressure versus density.”

Following experiments on the two big machines, researchers developed tables of gold and platinum responses to extreme pressure. “These will provide a standard to help future researchers calibrate the responses of other metals under similar stress,” said Jean-Paul Davis, another paper author and Sandia’s lead scientist in the effort to reliably categorize extreme data.

Data generated by experiments at these pressures — roughly 1.2 terapascals (a terapascal is 1 trillion pascals), an amount of pressure relevant to nuclear explosions — can aid understanding the composition of exoplanets, the effects and results of planetary impacts, and how the moon formed.

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The complete target assembly inside Sandia National Laboratories’ Z machine for the high-pressure materials experiments coordinated with researchers at Lawrence Livermore National Laboratory. The samples are covered by probes. Photo: Leo Molina.

The technical unit called the pascal is so small it is often seen in its multiples of thousands, millions, billions or trillions. It may be easier to visualize the scale of these effects in terms of atmospheric pressure units. The center of the Earth is approximately 3.6 million times the atmospheric pressure at sea level, or 3.6 million atmospheres. Z’s data reached 4 million atmospheres, or four million times atmospheric pressure at sea level, while the National Ignition Facility reached 12 million atmospheres.

The force of the diamond anvil

Remarkably, such pressures can be generated in the laboratory by a simple compression device called a diamond anvil.

However, “We have no standards for these extreme pressure ranges,” said Davis. “While investigators see interesting events, they are hampered in comparing them with each other because what one researcher presents at 1.1 terapascals is only 0.9 on another researcher’s scale.”

What’s needed is an underlying calibration tool, such as the numerical table these experiments helped to create, he said, so that scientists are talking about results achieved at the same documented amounts of pressure.

“The Z-NIF experiments will provide this,” Davis said.

The overall experiments, under the direction of Lawrence Livermore researcher D. E. Fratanduono, relied on Z machine’s accuracy as a check on NIF’s power.

Z’s accuracy, NIF’s power

Z’s force is created by its powerful shockless magnetic field, generated for hundreds of nanoseconds by its 20 million-ampere pulse. For comparison, a 120-watt bulb uses one ampere.

The accuracy of this method refocused the higher pressures achieved using NIF methods.

NIF’s pressures exceeded those at the core of the planet Saturn, which is 850 gigapascals. But its laser-compression experiments sometimes required a small shock at the start of the compression wave, raising the material’s temperature, which can distort measurements intended to set a standard.

“The point of shockless compression is to keep the temperature relatively low for the materials being studied,” said Seagle. “Basically the material does heat as it compresses, but it should remain relatively cool — hundreds of degrees — even at terapascal pressures. Initial heating is a troublesome start.”

Another reason that Z, which contributed half the number of “shots,” or firings, and about one-third the data, was considered the standard for results up to 400 gigapascals was because Z’s sample size was roughly 10 times as big: 600 to 1,600 microns thick compared with 60 to 90 microns on NIF. A micron is a thousandth of a millimeter.

Larger samples, slower pulses equal easier measurements

“Because they were larger, Z’s samples were less sensitive to the microstructure of the material than were NIF’s,” said Davis. “Larger samples and slower pulses are simply easier to measure to high relative precision. Combining the two facilities really tightly constrained the standards.”

Combining Z and NIF data meant that the higher-accuracy, but lower-intensity Z data could be used to pin down the low-to-medium pressure response, and with mathematical adjustments, reduce error on the higher-pressure NIF data.

“The purpose of this study was to produce highly accurate pressure models to approximately one terapascal. We did that, so this combination of facilities has been advantageous,” said Seagle.

See the full article here .


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Operated by Lawrence Livermore National Security, LLC, for the Department of Energy’s National Nuclear Security Administration

DOE’s Lawrence Livermore National Laboratory (LLNL) (US) is an American federal research facility in Livermore, California, United States, founded by the University of California-Berkeley (US) in 1952. A Federally Funded Research and Development Center (FFRDC), it is primarily funded by the U.S. Department of Energy (DOE) and managed and operated by Lawrence Livermore National Security, LLC (LLNS), a partnership of the University of California, Bechtel, BWX Technologies, AECOM, and Battelle Memorial Institute in affiliation with the Texas A&M University System (US). In 2012, the laboratory had the synthetic chemical element livermorium named after it.

LLNL is self-described as “a premier research and development institution for science and technology applied to national security.” Its principal responsibility is ensuring the safety, security and reliability of the nation’s nuclear weapons through the application of advanced science, engineering and technology. The Laboratory also applies its special expertise and multidisciplinary capabilities to preventing the proliferation and use of weapons of mass destruction, bolstering homeland security and solving other nationally important problems, including energy and environmental security, basic science and economic competitiveness.

The Laboratory is located on a one-square-mile (2.6 km^2) site at the eastern edge of Livermore. It also operates a 7,000 acres (28 km2) remote experimental test site, called Site 300, situated about 15 miles (24 km) southeast of the main lab site. LLNL has an annual budget of about $1.5 billion and a staff of roughly 5,800 employees.

LLNL was established in 1952 as the University of California Radiation Laboratory at Livermore, an offshoot of the existing UC Radiation Laboratory at Berkeley. It was intended to spur innovation and provide competition to the nuclear weapon design laboratory at Los Alamos in New Mexico, home of the Manhattan Project that developed the first atomic weapons. Edward Teller and Ernest Lawrence, director of the Radiation Laboratory at Berkeley, are regarded as the co-founders of the Livermore facility.

The new laboratory was sited at a former naval air station of World War II. It was already home to several UC Radiation Laboratory projects that were too large for its location in the Berkeley Hills above the UC campus, including one of the first experiments in the magnetic approach to confined thermonuclear reactions (i.e. fusion). About half an hour southeast of Berkeley, the Livermore site provided much greater security for classified projects than an urban university campus.

Lawrence tapped 32-year-old Herbert York, a former graduate student of his, to run Livermore. Under York, the Lab had four main programs: Project Sherwood (the magnetic-fusion program), Project Whitney (the weapons-design program), diagnostic weapon experiments (both for the DOE’s Los Alamos National Laboratory(US) and Livermore laboratories), and a basic physics program. York and the new lab embraced the Lawrence “big science” approach, tackling challenging projects with physicists, chemists, engineers, and computational scientists working together in multidisciplinary teams. Lawrence died in August 1958 and shortly after, the university’s board of regents named both laboratories for him, as the Lawrence Radiation Laboratory.

Historically, the DOE’s Lawrence Berkeley National Laboratory (US) and Livermore laboratories have had very close relationships on research projects, business operations, and staff. The Livermore Lab was established initially as a branch of the Berkeley laboratory. The Livermore lab was not officially severed administratively from the Berkeley lab until 1971. To this day, in official planning documents and records, Lawrence Berkeley National Laboratory is designated as Site 100, Lawrence Livermore National Lab as Site 200, and LLNL’s remote test location as Site 300.

The laboratory was renamed Lawrence Livermore Laboratory (LLL) in 1971. On October 1, 2007 LLNS assumed management of LLNL from the University of California, which had exclusively managed and operated the Laboratory since its inception 55 years before. The laboratory was honored in 2012 by having the synthetic chemical element livermorium named after it. The LLNS takeover of the laboratory has been controversial. In May 2013, an Alameda County jury awarded over $2.7 million to five former laboratory employees who were among 430 employees LLNS laid off during 2008.The jury found that LLNS breached a contractual obligation to terminate the employees only for “reasonable cause.” The five plaintiffs also have pending age discrimination claims against LLNS, which will be heard by a different jury in a separate trial.[6] There are 125 co-plaintiffs awaiting trial on similar claims against LLNS. The May 2008 layoff was the first layoff at the laboratory in nearly 40 years.

On March 14, 2011, the City of Livermore officially expanded the city’s boundaries to annex LLNL and move it within the city limits. The unanimous vote by the Livermore city council expanded Livermore’s southeastern boundaries to cover 15 land parcels covering 1,057 acres (4.28 km^2) that comprise the LLNL site. The site was formerly an unincorporated area of Alameda County. The LLNL campus continues to be owned by the federal government.

LLNL/NIF

DOE Seal

NNSA

Sandia Campus.

DOE’s Sandia National Laboratories (US) managed and operated by the National Technology and Engineering Solutions of Sandia (a wholly owned subsidiary of Honeywell International), is one of three National Nuclear Security Administration(US) research and development laboratories in the United States. Their primary mission is to develop, engineer, and test the non-nuclear components of nuclear weapons and high technology. Headquartered in Central New Mexico near the Sandia Mountains, on Kirtland Air Force Base in Albuquerque, Sandia also has a campus in Livermore, California, next to DOE’sLawrence Livermore National Laboratory(US), and a test facility in Waimea, Kauai, Hawaii.

It is Sandia’s mission to maintain the reliability and surety of nuclear weapon systems, conduct research and development in arms control and nonproliferation technologies, and investigate methods for the disposal of the United States’ nuclear weapons program’s hazardous waste.

Other missions include research and development in energy and environmental programs, as well as the surety of critical national infrastructures. In addition, Sandia is home to a wide variety of research including computational biology; mathematics (through its Computer Science Research Institute); materials science; alternative energy; psychology; MEMS; and cognitive science initiatives.

Sandia formerly hosted ASCI Red, one of the world’s fastest supercomputers until its recent decommission, and now hosts ASCI Red Storm supercomputer, originally known as Thor’s Hammer.


Sandia is also home to the Z Machine.

The Z Machine is the largest X-ray generator in the world and is designed to test materials in conditions of extreme temperature and pressure. It is operated by Sandia National Laboratories to gather data to aid in computer modeling of nuclear guns. In December 2016, it was announced that National Technology and Engineering Solutions of Sandia, under the direction of Honeywell International, would take over the management of Sandia National Laboratories starting on May 1, 2017.