Magnetic field imaging of a model electric motor using polarized pulsed neutrons at J-PARC/MLF

We have been developing a magnetic field imaging method using polarized pulsed neutrons for quantitative evaluation of magnetic fields in industrial equipment. To reduce the power loss of these products, it is important to quantitatively evaluate the distribution of not only strength but also direction of the internal field. In this study, we attempted to visualize the directional distribution of a magnetic field in a model electric motor. Because of the limited wavelength range that we could use in the present analysis, the polarization distribution image of the model motor was confirmed to reflect the directional distribution of the magnetic field outside the motor. It was also clarified that usage of shorter wavelength neutrons would enable us to visualize the field inside the motor. Then polarized neutron imaging was found to be a potentially powerful method for observing the directional distribution of the driving field of a rotating motor.