Dynamic Behaviour of Fast-Pulsed Quadrupole Magnets for LINAC4 Transfer Line

Linac4, recently built at CERN, is a linear normal conducting accelerator for negative hydrogen ions (H⁻). A new transfer line will link Linac4 to the Proton Synchrotron Booster. This transfer line includes 21 quadrupole magnets characterized by fast excitation cycles, which make accurate magnetic measurements challenging. This paper describes the method used for the measurement, which is a combination of techniques based on rotating and fixed search coils. We show how these instruments can be used in a complementary way to derive information on different aspects of the magnetic behaviour of these quadrupoles, such as the impact of hysteresis and dynamic eddy current effects.