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X-rays: More than meets the eye

X-rays are vital tools at NNSA. They help scientists study how plutonium ages and explore how inertial confinement fusion works.

National Nuclear Security Administration

June 25, 2025
An illustration showing the NNSA logo and the word X-RAY, in the middle is a whimsical black-and-white illustration of a skeleton holding a beaker. The skeleton is wearing protective goggles and a bowtie. The bottom of the illustration shows where X-rays appear in the electromagnetic spectrum.

X-ray technology has come a long way since Wilhelm Röntgen’s ghostly portraits of his wife’s hand bones. Beyond airport security or your dentist’s office, X-rays are now vital tools at NNSA. They help scientists study how plutonium ages and explore how inertial confinement fusion works.

Picturing Stockpile Stewardship
A diagram showing the Scorpius project. On the left, it shows a map of the NNSS along with logos of the participating organizations, including NNSS, LANL, NNSS, and LLNL. Then it shows a map of the extensive tunneling and a tunnel that has acceleration and an arrow on it. Finally, at the bottom are images of the containment vessel, the mechanisms that are accelerating the electrons, and the injector.
Scorpius will perform experiments in its underground location over 30 years.
A graphic showing what Scorpius does on the inside. An accelerator focuses the pulsed electron beam on a target, which converts the beam to X-rays, which go through the test object. Behind the test object is a scintillator that converts X-rays to visible light and a turning mirror that focuses on a sensor, which allows technicians to record the image.
A short burst of intense X-rays will pass through the plutonium and Scorpius will convert the detected X-rays into high-resolution radiographic images.

Nuclear weapons in America’s stockpile are designed to sit idle, yet ready, for decades. So how do ensure they’ll work if ever needed? One answer lies in using X-rays to examine tiny amounts of plutonium during subcritical experiments.

Deep underground, in the desert northwest of Las Vegas, teams from Los Alamos National Laboratory, Lawrence Livermore National Laboratory, Sandia National Laboratories, and the Nevada National Security Sites are building Scorpius—a 400-foot-long, 1,000-ton machine designed to create incredibly detailed X-ray images of plutonium under pressure.

At its heart is a steel vessel about the size of a washing machine. Inside, researchers place a speck of plutonium along with explosives. After sealing the vessel and clearing the area, they initiate the experiment. The explosion compresses the plutonium, triggering a controlled, non-self-sustaining fission reaction. 

In that split second, Scorpius fires intense X-rays at the reaction to create a radiograph —much like a dental X-ray, but far more powerful. These images help researchers understand how weapons materials behave as they age.

A man dressed in a jacket and holding a notebook gestures to a large metal mechanism that looks electrical. It has dozens of yellow bulb-like items sticking out in rows.
Bob Webster of Los Alamos National Laboratory and his colleagues discuss a prototype of one of the 100+ modules that will be needed for Scorpius.
Extreme experiments call for extreme machines
A colorful image of reds, blues, and purples. Hundreds of wires light up during a Z-machine shot, seeming to crackle with blue energy as they connect to darker parts of the machine. Although it looks larger because of the lens, the machine is about 20 feet in diameter and 10 feet high.
The Z Machine at Sandia National Laboratories uses magnetic fields and electrical currents to recreate the extreme radiation, pressure, and temperatures produced by a nuclear blast.

Meet Z: Sandia National Laboratories’ Z Pulsed Power Facility, which uses magnetic fields and electrical currents to recreate the extreme radiation, pressure, and temperatures produced by a nuclear blast. The Z machine is vital to NNSA’s mission of maintaining a safe and reliable nuclear stockpile. And it helps scientists study materials in those weapons as time goes by. 

It’s the most powerful machine of its kind in the world. It uses the same amount of electricity needed to light 100 homes for a few minutes. But it takes that energy and compresses it to produce an electrical power pulse that is 5-10 times greater than all the power generated on Earth – for a fraction of a second.

That extreme power pulse heats and compresses materials and produces X-rays at weapon-like conditions. This supports Sandia’s research in high-energy density science.

The Z machine is part of Sandia's Pulsed Power program, which began in the 1960s and has been expanding our understanding of dynamic materials, radiation effects, and inertial confinement fusion ever since. 

Research at NNSA spans the entire electromagnetic spectrum – take a look at findings at other frequencies and how they help further the missions of the Nuclear Security Enterprise.

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