Muon capture is the capture of a negative

muon A muon ( ; from the Greek letter mu (μ) used to represent it) is an elementary particle similar to the electron, with an electric charge of −1 '' e'' and a spin of , but with a much greater mass. It is classified as a lepton. As wit ...

by a

proton A proton is a stable subatomic particle, symbol , H+, or 1H+ with a positive electric charge of +1 ''e'' elementary charge. Its mass is slightly less than that of a neutron and 1,836 times the mass of an electron (the proton–electron mass ...

, usually resulting in production of a

neutron The neutron is a subatomic particle, symbol or , which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons behav ...

and a

neutrino A neutrino ( ; denoted by the Greek letter ) is a fermion (an elementary particle with spin of ) that interacts only via the weak interaction and gravity. The neutrino is so named because it is electrically neutral and because its rest mass is ...

, and sometimes a

gamma Gamma (uppercase , lowercase ; ''gámma'') is the third letter of the Greek alphabet. In the system of Greek numerals it has a value of 3. In Ancient Greek, the letter gamma represented a voiced velar stop . In Modern Greek, this letter r ...

photon A photon () is an elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are massless, so they always m ...

. Muon capture by heavy nuclei often leads to emission of particles; most often

s, but charged particles can be emitted as well. Ordinary muon capture (OMC) involves capture of a negative muon from the atomic orbital without emission of a gamma photon: : + → _μ + Radiative muon capture (RMC) is a radiative version of OMC, where a gamma photon is emitted: : + → _μ + + Theoretical motivation for the study of muon capture on the proton is its connection to the proton's induced pseudoscalar form factor g_p.

Practical application - Nuclear waste disposal

Muon capture is being investigated for practical application in radioactive waste disposal, for example in the artificial transmutation of large quantities of long-lived

radioactive waste Radioactive waste is a type of hazardous waste that contains radioactive material. Radioactive waste is a result of many activities, including nuclear medicine, nuclear research, nuclear power generation, rare-earth mining, and nuclear weapons ...

that have been produced globally by fission reactors. Radioactive waste can be transmuted to stable isotopes following irradiation by an incident muon () beam from a compact proton accelerator source.

References

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Nagamine, Kanetada (2016) "Nuclear Waste Disposal Method and its apparatus using muon-nuclear-absorption". (WO2016143144A1)

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