Speaker
Description
Status of newly planned J-PARC muon g-2/EDM experiment will be reported. This experiment differs greatly from the BNL-E821 and FNAL-E989 experiments, which use a muon of magic momentum (γ=29.3). Utilizing low emittance muon beam with momentum of γ=3, we store the beam in 3T superconductive solenoidal magnet with orbit’s diameter of 0.66m. The sub-meter storage orbit allows us to reconstruct decayed positron momentum event-by-event, and to obtain vector of the muon spin precession. This is crucial to distinguish the muon g-2 component parallel to the magnetic field, and the EDM component perpendicular to the magnetic field, and allow us to measure these two physical quantities at a time, but independently with a same experimental setup.
In this presentation, we will introduce outline of newly developed three-dimensional spiral beam injection method to realize a new experiment at J-PARC. Two major R&D items are introduced: (1) X-Y coupling to store the beam in the axially symmetrical solenoid magnetic field (dedicated beam phase space control applying strong coupling between in the solenoidal-axial direction and the radial direction), (2) a vertical kicker device to control the beam motion from the injection trajectory to the store trajectory. We will also introduce results of demonstration experiment to judge feasibility of this new injection scheme. We successfully inject the electron beam with 0.24m diameter and store by use of a vertical kicker device, which is the same concept as original experiment. At the same time, however, several issues which should be considered towards the actual production are found and we will discuss them, too.
