Muon sources and detection technology in muon spin spectroscopy applications: a review

Muons, as second-generation leptons, have emerged as sensitive probes in both fundamental physics and applied sciences. They can be generated via the collisions of primary cosmic rays, accelerator particle beams, or laser-driven particles with atomic nuclei. In recent years, cosmic-ray muons have attracted extensive and growing interest for applications in muography and positioning. Accelerator-produced muons are artificial particles characterized by high intensity, narrow spatial distribution, and tight temporal distribution. In recent years, several muon source facilities in China have been either under construction or in the planning phase. Among the diverse applications enabled by this unique quantum probe, muon spin spectroscopy stands out as a key driver—it allows researchers to precisely measure the local magnetic properties of materials. This capability will significantly increase the development of relevant disciplines, including condensed matter physics, chemistry, environmental science, and energy science. In addition, laser-driven muon sources can reduce the size of man-made muon facilities by an order of magnitude, holding great potential for realizing table-top muon-based applications with performance comparable to those of accelerator-derived muon beams.