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It’s changed how scientists think about the sun and even led to new protocols in how the country safeguards its nuclear weapons.
Sandia National Laboratories’ Z machine has been contributing to breakthroughs in the study of black holes, faraway planets, nuclear bombs and fusion energy research for 25 years – an anniversary lab officials recently marked by bringing back several former program directors to visit the machine, which is locked behind security gates and monitored by cameras at Kirtland Air Force Base.
Daniel Sinars, the director of the Pulsed Power Sciences Center for Sandia, gave the Journal a tour of the facility last week, on a day when technicians in blue coveralls were cleaning up the aftermath of a Z shot taken the day before. The building smelled of transformer oil, the liquid that coats much of the high-voltage equipment, which was being drained and replaced.
Dozens of scientists and technicians are needed to use the machine, which has an operating budget of about $110 million per year, funded by the National Nuclear Security Administration, Sinars said.
“It takes us between 80 and 100 people to execute and experiment,” he said. “So this is the biggest operation at the laboratory in terms of the number of people that are doing one thing together.”
The machine can take about 150 “Z shots” or “Z pinches” per year. The energy used in a shot comes from large capacitors, which make a two-story, 33-foot-diameter circle, and it is fired into the core, which is about the size of your fingertip. It’s the world’s most powerful and efficient radiation source, according to Sandia’s website, and it destroys part of its target with each blast.
Sinars said about a third of the experiments are driven by the primary mission of the Z machine: protecting the country’s nuclear weapons. It does so by essentially creating a controlled blast as a proxy for a nuclear explosion.
Massive diagnostic recording equipment is positioned on all sides of the small target, which allows for detailed recordings of the burst. That data is then used to understand how items would respond in a nuclear blast, without actually having to detonate a weapon. “That was the origin of the laboratory, as a tool for understanding hostile environments,” Sinars said. “One of things we worry about with our nuclear weapons is having them survive a hostile environment. If you were to detonate one nuclear weapon near another. … And one of the missions of Sandia is (ensuring) our own nuclear weapons would survive that onslaught.”
Data from those experiments has been used by Los Alamos National Laboratory to make changes in the country’s nuclear weapons program, Sinars said.
The Z machine’s peak electrical power is about 80 trillion watts for a split second, which according to Sandia’s website is far more than all the world’s power plants combined.
In addition to classified tests aimed at protecting weapons, the Z machine also does “high novelty science,” Sinars said. Basically, that means using the machine with the goal of furthering the world’s understanding of space, black holes, planets and energy.
Those account for about 10% of Z machine experiments. Often the labs scientists partner with academics from universities.
For example, earlier this year, Sandia researchers published an article in Nature Communications about experiments the Z machine did on the mineral bridgmanite. By finding out bridgmanite properties, such as its melting point, the researchers deduced what it’s like on the surface of faraway planets. That provided insights into which ones are more likely to resemble Earth and could perhaps sustain life as we know it.
“Z has become the most energetic source of X-rays for fusion research and for stockpile stewardship on the planet,” Don Cook, a former director, said in a Sandia news release. “Its capabilities as a pre-eminent research facility for high energy density sciences are known and appreciated worldwide.”
Sinars said the Z machine experiments have changed astronomers’ understanding of the sun.
He said over the last 10 years, Z machine experiments have helped explain why various layers of the inside of the sun don’t appear where scientists originally believed they would be. That’s because the Sandia experiments, Sinars said, are showing that the understanding of iron opacity – how well X-rays are transmitted through iron plasmas – wasn’t a settled science.
“All these people can do computer simulations, but garbage in garbage out. If you don’t put the right material models or opacity models or other inputs into your simulation you can’t expect an accurate outlook,” Sinars said.
“A lot of what we do at Z on a very high level is directly create conditions and make measurements that can be used in simulations, simulations of the universe or simulations of a nuclear weapon.”
In the next 25 years, the Z machine is likely to play a key role in fusion energy research, Sinars said. About a third of Z machine experiments are dedicated to that pursuit, and the machine can fuse two atoms together.
Fusion energy is a proposed concept of using the energy released from fusing two atomic nuclei together, which would create renewable and clean energy sources.
Researchers are using the Z machine to do magnetized liner inertial fusion, where magnetic fields are used to create the pressure needed.
“I think we’ve pioneered and demonstrated some of the (fusion energy) ideas people have talked about. If there ever is a fusion energy source, it is much more likely to look like what we’ve been doing,” Sinars said. “We’re not big enough to get a sustained fusion reaction. But we are able to study the science of how to do that.”