No abstract

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.

A buncher cavity has been developed for the muons accelerated by a radio-frequency quadrupole linac (RFQ). The buncher cavity is designed for β = v/c = 0.04 at an operational frequency of 324 MHz. It employs a double-gap structure operated in the TEM mode for the required effective voltage with compact dimensions, in order to account for the limited space of the experiment. The measured resonant frequency and unloaded quality factor are 323.95 MHz and 3.06 × 10 3 , respectively. The buncher cavity was successfully operated for longitudinal bunch size measurement of the muons accelerated by the RFQ.

No abstract

No abstract