Laser-Driven Muons Produced an Object Image in a 42-Metre Test

A high-power laser experiment has produced an object image using artificially generated muons, particles able to cross dense material that blocks many other forms of radiation. The international team reports that its measurement line extended up to 42 metres from the source and that the recorded beam profile and object image agreed with Monte Carlo simulations for muons carrying energies of a few gigaelectronvolts.

The work was posted to arXiv on September 23 and updated on September 25. It has not yet been peer reviewed. The authors describe it as the first imaging demonstration dominated by an artificial, laser-driven muon beam. That wording matters because earlier experiments had already detected laser-produced muons, and a separate July preprint reported single-shot radiography from a mixed secondary beam containing muons, pions and neutrons.

The new step is not merely making muons. It is showing that the penetrating signal can be measured as a directed beam and used to form an object image.

How the beam was made

The laser pulse travelled through a gas target and created a plasma wave capable of accelerating electrons over a much shorter distance than a conventional radio-frequency accelerator. Those electrons then struck a high atomic-number converter. Energetic photons created in the collision produced positive and negative muon pairs through the Bethe-Heitler process.

Muon imaging usually relies on particles created when cosmic rays hit the atmosphere. They arrive everywhere for free, but their low flux can make a scan take days, weeks or longer. An artificial source could direct more particles through a chosen object and shorten the exposure. The same basic principle could eventually support checks of cargo, industrial structures, geological formations or shielded nuclear material.

What was actually demonstrated

The researchers used muography detectors to measure where the particles arrived and how the target changed their distribution. They compared the measurements with particle-transport simulations rather than assuming that every recorded event was a muon. The agreement supported their interpretation that the image-forming component was dominated by laser-generated muons with energies of several GeV.

A 2023 simulation study from the same ELI-NP research line had predicted that such sources could reveal dense material in minutes. The new experiment advances beyond that numerical forecast, but it does not establish the speed, resolution, reliability or operating cost required for a field scanner.