Muon Profile Measurement After Acceleration With a Radio-Frequency Quadrupole Linac

We have measured the muon beam profile after acceleration using a radio frequency quadrupole linac (RFQ). Positive muons are injected to an aluminum degrader and negative muoniums (Mu−) are generated. The generated Mu−'s are extracted by an electrostatic lens and accelerated to 89 keV by the RFQ. The accelerated Mu−'s are transported to a beam profile monitor (BPM) through a quadrupole magnet pair and a bending magnet. The BPM consists of a micro-channel plate, a phosphor screen, and a CCD camera. The measured profile in the vertical direction is consistent with the simulation. This profile measurement is one of the milestones for realizing a muon linac for measurement of the muon anomalous magnetic moment at the Japan Proton Accelerator Research Complex.