Calibration Experiment of Equivalent Area of Induction Coil for Magnetic Field Measurement of Superconducting Cyclotron

China Institute of Atomic Energy’s 250MeV superconducting cyclotron (CYCIAE-250) uses the induction coil method to measure the magnetic field in its airgap. To ensure the precision of magnetic field measurement, area of the induction coil needs to be calibrated. This paper designs a set of coil calibration technique based on flipping coil method. The uniform magnetic field needed for calibration is provided by a permanent magnet with good static performance, its field is measured through high-precision nuclear magnetic resonance(NMR) probe. Then the induction coil will then be installed at the same position of the NMR probe. During the calibration process, induction coil is rotated 180 degrees and magnetic flux through it will be recorded by a high-speed digital integrator. Corresponding equipment is also designed to finish this task. This Paper describes this magnetic field measurement method, corresponding magnetic measurement equipment, calibration process of the induction coil and calibrated area of the coil.