https://en.wikipedia.org/wiki/Muon_tomography:

“Muon tomography or muography is a technique that uses cosmic ray muons to generate two or three-dimensional images of volumes using information contained in the Coulomb scattering of the muons.

[…]

Since 2010s researchers are also exploring and attempting to use artificially generated muons—created by conventional accelerators or laser-plasma systems—for muon tomography.”

I may overlook something, but skimming the references, I get the impression the latter still is an idea. References are about simulating the machinery, discussing requirements of hypothetical machines, etc.