Measurements of the integrated gradient for Halbach-type permanent magnet quadrupoles

A new method of measuring the integrated gradient of quadrupoles using a Hall probe is described. The proposed method is developed to measure a Halbach-type permanent magnet quadrupole (PMQ), whose roll angle is difficult to determine for alignment in the measurement. In the proposed method, we establish a roll angle alignment for the magnet, Hall probe, and motor stage based on the field distribution. The proposed method is analyzed and experimentally verified, and a setup is built. Measurement results have confirmed its feasibility for measuring the integrated gradient of PMQs with favorable reproducibility. This method is also an optional method for measuring the integrated gradient of electromagnets.