Study of Magnetic Field Measurement System for g-2/EDM Experiment at J-PARC

Two magnetic field monitoring systems for g-2/EDM experiment at J-PARC are developed. One is a continuous-wave NMR magnetometer, which is used to measure the field homogeneity in a muon storage region. The other is a Hall effect magnetometer, which is used to measure the magnetic field around the muon injection region and that for focusing the muon beam. In order to improve the accuracy of the commercial NMR magnetometer, a digital signal processing system was implemented instead of an analog one. As for the Hall probe system, a three-axis Helmholtz coil system was fabricated to measure tilt angles of Hall sensors in a three-axis Hall probe. The field homogeneity of each Helmholtz coil was measured, and the result agreed well with the design values.