Los Alamos National Laboratory

Los Alamos National Laboratory

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Muon Tomography

Physics Division is harnessing cosmic-ray muons to thwart nuclear smugglers and peer inside damaged nuclear reactors.


Award-winning detection technologies

Cosmic-ray muons, produced when cosmic rays strike the upper atmosphere, are subatomic particles that shower down on Earth, passing unnoticed through our bodies, cars, and homes.

Muon tomography, an imaging technique Los Alamos scientists pioneered in 2002 following the 9/11 terrorist attacks, uses naturally occurring muons to detect and identify nuclear threat materials, such as uranium and plutonium, based on their atomic number and density. Unlike other imaging and detection techniques, such as x-rays, muon tomography cannot be fooled by threat materials that have been shielded because the dense shielding material is itself detected.

Companies have commercialized the approach

The technology to create the first full-scale operational scattering muon radiography system for sea container scanning was developed under a cooperative research and development agreement between Los Alamos and Decision Sciences International Corporation. The company has constructed and deployed portal monitors at various locations. Capable of screening a 40-foot ship container in approximately 45 seconds, this technology was recognized in 2013 by R&D Magazine with an R&D 100 Award.

Muon tomography also is effective for nuclear reactor imaging and treaty verification.

Within weeks of the disastrous 2011 tsunami and earthquake in Japan, the Los Alamos Muon Radiography Team began investigating whether the Los Alamos method could be used to image the location of nuclear materials within the damaged Fukushima Daiichi reactors. Following a successful demonstration test, Toshiba Corporation partnered with Los Alamos to use muon tomography to safely image the cores of the reactors.

Watch: Looking Inside Fukushima Daiichi with Muon Tomography

Brief history

In the mid-1990s, scientists at Los Alamos were developing proton radiography techniques for a variety of applications. During the course of their work, they contemplated the idea of using muons instead of protons. The resulting technology is known as muon scattering tomography, a breakthrough variation of muon tomography, which had been around since the 1950s.

Muon tomography uses cosmic-ray muons—subatomic particles similar to electrons—to generate three-dimensional images.