Lab Report

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The Lab Report is a weekly compendium of media reports on science and technology achievements at Lawrence Livermore National Laboratory. Though the Laboratory reviews items for overall accuracy, the reporting organizations are responsible for the content in the links below.

Jun. 08, 2018

In this illustration, the grid in the background represents the computational lattice that theoretical physicists used to calculate a particle property known as nucleon axial coupling. Credit: Evan Berkowitz/Jülich Research Center

Life and death of a neutron

Researchers are using supercomputers to better understand the mysteries of the subatomic world.

Experiments that measure the lifetime of neutrons reveal a perplexing and unresolved discrepancy. While this lifetime has been measured to a precision within 1 percent using different techniques, apparent conflicts in the measurements offer the exciting possibility of learning about as-yet undiscovered physics.

Now, scientists, including those from Lawrence Livermore, have enlisted powerful supercomputers to calculate a quantity known as the “nucleon axial coupling,” or gA – which is central to understanding a neutron’s lifetime – with an unprecedented precision. Their method offers a clear path to further improvements that may help to resolve the experimental discrepancy.

Time-integrated image of a laser-driven shock compression experiment to recreate planetary interior conditions and study the properties of superionic water. Image by M. Millot/E. Kowaluk/J.Wickboldt/LLNL/LLE/NIF

That water is so weird

Scientists have confirmed a form of water that is simultaneously solid and liquid. It is the latest advance in the study of water, a seemingly simple substance that can shift between many different configurations.

"That's a really strange state of matter," said Marius Millot, a physicist at Lawrence Livermore National Laboratory, the lead author of a paper published in the journal Nature Physics that describes the experiments.

This new form, called superionic water, consists of a rigid lattice of oxygen atoms through which positively charged hydrogen nuclei move. It is not known to exist naturally anywhere on Earth, but it may be bountiful farther out in the solar system, including in the mantles of Uranus and Neptune.

Researchers (from left) Phil Depond, Nick Calta, Aiden Martin and Jenny Wang are part of a multi-lab team that has successfully designed, built and tested a portable diagnostic machine capable of probing inside metal parts during additive manufacturing. Image by Julie Russell/LLNL

Peering inside metal manufacturing

A team of researchers at Lawrence Livermore National Laboratory (LLNL) has successfully designed, built and tested a portable diagnostic machine that uses X-ray imaging to "probe" the inside of metal parts during laser powder bed fusion (PBF), revealing many of the complex mechanisms that can drive defect formation and limit part quality in metal additive manufacturing. The research is being carried out in partnership with SLAC National Accelerator Laboratory and Ames Laboratory, funded by the Department of Energy’s Energy Efficiency and Renewable Energy (EERE) Advanced Manufacturing Office.

The portable diagnostic machine, capable of probing the melt pool, was developed and designed by LLNL researcher Nick Calta and his team. At the Stanford Synchrotron Radiation Lightsource at SLAC, researchers were able to evaluate the method and successfully observe melt pool dynamics beneath the surface, providing researchers with new insights into the process. The research was published earlier this month in the Review of Scientific Instruments.

LLNL scientists Katelyn Mason and Deon Anex prepare to pulverize forensic bone samples prior to demineralization and extraction of proteins to find identity markers. Photo by Julie Russell/LLNL

No bones about it

When a team of researchers led by Lawrence Livermore National Laboratory (LLNL) developed a new biological identification method that exploits information encoded in proteins, they thought it could have multiple applications. Nearly two years later, they've turned out to be right.

In September 2016, LLNL scientists announced they had developed a science-based, statistically validated way to use protein markers from human hair to identify people and link individuals to evidence.

Now they've found a second way to use protein markers from human tissue for identification—this time from bones. Their work is described in a paper published online by Forensic Science International, an Amsterdam-based journal.

"One of the most exciting aspects of this research is that it seeks to provide a completely new objective methodology for human identification," said LLNL chemist Brad Hart, the director of LLNL's Forensic Science Center and a co-author of the paper.

Martian meteorite Northwest Africa (NWA) 7034, nicknamed "Black Beauty," weighs approximately 11 ounces (320 grams). Credit: Carl Agee/University of New Mexico

Unlocking the secrets of Mars

Back in 2011, a Martian meteorite was found in the Sahara Desert. The official name of the 320-gram rock is Northwest Africa (NWA) 7034, but it is also known by the nickname "Black Beauty."

Scientists knew from previous studies of rock samples from Mars that Black Beauty was special, and now, thanks to a recent study by researchers at Lawrence Livermore National Laboratory, more secrets about how and when the planet's crust formed have finally been unlocked.

NWA 7043 is an example of breccia, which means that it is made up of different kinds of rocks that were mixed and fused together by heat (sintered). Its unique makeup allowed the researchers to learn more about the Mars' crust than they could from a rock collected from the surface.

Using various chronometry methods (the science of time measurement), researchers were able to determine the approximate age of the meteorite at 4.4 billion years old.