A Novel Method for Transverse Beam-Coupling Impedance Measurements in Particle Accelerator Devices Using the Bead-Pull Method

In high-energy particle accelerators, circulating particle beams with high intensity interact electromagnetically with their surroundings (i.e., metallic vacuum chambers of various geometries). These electromagnetic interactions, which are typically described through the concept of beam-coupling impedance, can represent a serious issue in terms of stability of the particle beam and heating on the accelerator structures. It is therefore crucial to account for beam-coupling impedance through simulations and measurements during the design phase of an accelerator component. However, standard methods used in the accelerator field have known limitations due to the perturbations that they induce in the device geometry. Thus, the bead-pull method, which is a possible alternative approach, is presented in this study. The longitudinal beam-coupling impedance measurement technique is introduced, and it is further developed for novel use in transverse impedance measurements. © 1963-2012 IEEE.