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.

May. 01, 2015

asteroid
Simulation of a 10-ton mass impacting Asteroid Golevka (about 500 meters across) at 10 km/s, using the Spheral code (arrow denotes direction of impact). Image by Megan Bruck Syal/LLNL and J. Michael Owen/LLNL.

Changing an asteroid's course

In 2013, a small meteor exploded in the atmosphere over Chelyabinsk, Russia. The Chelyabinsk meteor was a relatively small chunk of space rock — asteroid researchers think it was probably about 20 meters (66 feet) across — but exploding over a city made it a noteworthy event.

It's probable many similar asteroids hit Earth on a regular basis. Many people are looking at viable options for planetary defense: destroying or turning asteroids aside before they can hit Earth.

One of those researchers is Megan Bruck Syal of Lawrence Livermore National Laboratory, who is looking into more sensible asteroid mitigation strategies: using some kind of heavy mass called a "kinetic impactor" or nuclear explosion to gently nudge the asteroid off course. The idea is similar for both. Since Earth presents a relatively small target compared with the vastness of empty space in the solar system, even a small change in an asteroid's orbit would cause it to miss the planet, provided intervention comes early enough.
 

aerogel
Lawrence Livermore researchers have made graphene aerogel microlattices with an engineered architecture via a 3D printing technique known as direct ink writing. Illustratiion by Ryan Chen/LLNL

Better batteries through engineering

Aerogels have long been one of those "gee whiz" materials that gets people to take notice — watching a solid float on air tends to do that. Aerogels are essentially a gel in which the liquid component of the gel has been replaced with gas.

Researchers at Lawrence Livermore National Laboratory have produced an aerogel out of graphene that could have applications ranging from electronics to energy storage. Boosting the "gee whiz" factor: The new material is produced through 3-D printing.

The LLNL research team was able to produce a predetermined architecture for a graphene-based aerogel, which previously had always been random, by using 3-D printing. By defining the architecture, the researchers were able to improve the material’s performance.

container
A new detector developed in part by Lawrence Livermore scientists can precisely pinpoint the source of nuclear material in shipping cargo containers.

Security on the go

Scientists are developing a portable technology that will safely and quickly detect nuclear material hidden within large objects such as shipping cargo containers or sealed waste drums.

The researchers, including Lawrence Livermore scientists, have been awarded more than $10 million from the Department of Energy's National Nuclear Security Administration Defense Nuclear Nonproliferation R&D Office to combine the capabilities of conventional building-size research instruments with the transportable size of a truck for security applications on the go.

The core of the detection system is a next-generation source of high-energy photons, often referred to as X-rays or gamma rays.

The compact photon source allows users to produce MeV photons within very specific narrow ranges of energy, an improvement that will allow the fabrication of highly sensitive yet safe detection instruments to reach where ordinary passive handheld sensors cannot, and to identify nuclear material such as uranium-235 hidden behind thick shielding. The ability to choose the photon energy is what would allow increased sensitivity and safety.

 

coal_plant
A wind farm provides electricity.

Carbon dioxide as an energy source

Carbon dioxide generated by burning fossil fuels and other human activities is a big problem when it comes to climate change. Researchers say that it may be possible not only to capture and store CO2 in the ground, but to transform it into the equivalent of a battery that would store energy from renewable sources and solve the supply fluctuations that hinder them as a replacement for coal.

An international group of scientists, which includes Lawrence Livermore National Laboratory researcher Tom Buscheck, has proposed to store energy generated by renewable sources such as wind and solar power when electrical demand is low, and then tap into it at peak times. (The system also could store energy generated by burning coal as well.)

That ability to store renewable energy would solve two problems at once. It would help create an economic incentive for carbon capture and sequestration, which has been slow to develop because it doesn’t make money for power companies. Second, the storage would make renewable energy available even at times when the wind dies down or the sun is behind clouds.

array
To drive the diode arrays, LLNL needed to develop a completely new type of pulsed-power system. Photo by Damien Jemison

A peak power-house

Lawrence Livermore National Laboratory has installed and commissioned the highest-peak-power laser-diode arrays in the world, which in total produce a peak power of 3.2 MW. The diode arrays will act as the primary pump source for the High-Repetition-Rate Advanced Petawatt Laser System (HAPLS), currently under construction at LLNL.

When completed, the HAPLS laser system will be installed at the European Union’s Extreme Light Infrastructure (ELI) Beamlines facility, which is under construction in the Czech Republic. The HAPLS is being built and commissioned at LLNL and will be installed and integrated into the ELI Beamlines facility starting in 2017.

HAPLS will be capable of generating 30 femtosecond pulses with peak powers greater than a petawatt at a repetition rate of 10 Hz. The high repetition rate is possible because, unlike existing petawatt lasers, which are flashlamp-pumped, HAPLS is pumped by diode arrays capable of delivering kilojoule pulses at high repetition rates to the final power amplifier.