First muon acceleration using a radio-frequency accelerator

Muons have been accelerated by using a radio-frequency accelerator for the first time. Negative muonium atoms (Mu-), which are bound states of positive muons (μ+) and two electrons, are generated from μ+'s through the electron capture process in an aluminum degrader. The generated Mu-'s are initially electrostatically accelerated and injected into a radio-frequency quadrupole linac (RFQ). In the RFQ, the Mu-'s are accelerated to 89 keV. The accelerated Mu-'s are identified by momentum measurement and time of flight. This compact muon linac opens the door to various muon accelerator applications including particle physics measurements and the construction of a transmission muon microscope.