Muon-catalyzed nuclear fusion.
(1) A beam of negatively charged muons is produced and injected into a mixed fuel of deuterium and tritium, (2) resulting in the creation of many muonic tritium atoms (tµ). As muons are 207 times heavier than electrons, the muon orbits the nucleus at a much closer distance to the nucleus than electrons. Thus, tµ atoms are extremely small. (3) As the tµ atoms have no electric charge, they readily collide with deuterium atoms without being affected by repulsive electrical force. These collisions produce dtµ molecules, which consist of a muon, a deuterium nucleus and a tritium nucleus. (4) Similar to tµ atoms, dtµ molecules are extremely small. When d–t nuclear fusion occurs in these small molecules, large amounts of energy are released, accompanied by the production of α particles (helium nuclei) and neutrons. (5) The muon is freed and recycled in subsequent nuclear fusion reactions. (6) About 1% of the liberated muons, however, become stuck to helium nuclei.
The new Muon Science Facility (MUSE) now under construction at J-PARC in Tokai, Japan, will produce intense muon beams with fluxes several orders of magnitude higher than at present muon facilities allowing many novel experimental studies that were statistically not feasible until now. The investigation of the nuclear properties of unstable nuclei using muonic atom X-ray spectroscopy would become a unique tool to increase our knowledge of the nuclear structure far from stability, i.e., the nuclear charge distribution and the deformation properties of nuclei. Muonic atom spectroscopy has been successfully used for many years to determine the nuclear charge distribution.