Determining beam transverse absolute position by triangulation of multi-electrode signal phase differences

Abstract

Accurate measurement of the transverse position of a beam is crucial in particle accelerators because it plays a key role in determining the beam parameters. Existing methods for beam-position measurement rely on the detection of image currents induced on electrodes or narrow-band wake field induced by a beam passing through a cavity-type structure. However, these methods have limitations. The indirect measurement of multiple parameters is computationally complex, requiring external calibration to determine the system parameters in advance. Furthermore, the utilization of the beam signal information is incomplete. Hence, this study proposes a novel method for measuring the absolute electron beam transverse position. By utilizing the geometric relationship between the center position of the measured electron beam and multiple detection electrodes and by analyzing the differences in the arrival times of the beam signals detected by these electrodes, the absolute transverse position of the electron beam crossing the electrode plane can be calculated. This method features absolute position measurement, a position sensitivity coefficient independent of vacuum chamber apertures, and no requirement for a symmetrical detector electrode layout. The feasibility of this method is validated through numerical simulations and beam experiments.