Magnetic field measurement of the air slot dipole magnet

Field measurement results of the air slot type dipole magnet are presented. The vacant portion, called the air slot, located in the iron core controls the flow of the magnetic flux and improves uniformity of the magnetic field. This magnet realizes a better magnetic field distribution over a wide range of field strengths. The prototype of the magnet had been fabricated and tested to verify the design principle. The results of measurements by the Hall-probe showed good agreement with the numerical calculations for magnetic field strengths ranging from 0.27 T to 1.83 T. The field uniformity Δ B/B was below 0.04% in the good field region