Comparative Studies of Three-Dimensional Analysis and Measurement for Establishing Pulse Electromagnet Design

A new horizontal shift bump electromagnet for the J-PARC 3-GeV RCS injection bump system was designed and fabricated. The bump magnet is a pulse magnet that repeatedly excites a trapezoidal waveform of about 1.5 ms duration at 25 Hz. And it is possible to change of the rising and falling time of the pulse waveform with the maximum current of 16 kA and the voltage of 12 kV between 150 and 500 microseconds according to the optimum beam generation condition. In order to design such magnets of such specifications, three-dimensional dynamic magnetic field analysis capable of evaluating eddy currents is required. Using one electromagnet model, comparison of static magnetic field analysis with dynamic magnetic field analysis, and two-dimensional calculations with three-dimensional ones were studied. In addition, we also confirmed the difference between the analysis and measurements as well as the difference of the magnetic field measurement method between the search coil and the Hall probe. We could then have established a pulse electromagnet design method.