TITLE:
Radio Frequency Quadrupole for Bunching Electron Beam: Electromagnetic Field, Particle Velocity Range, and Accuracy at 10 GHz
AUTHORS:
Serigne Bira Gueye
KEYWORDS:
Electron RF Quadrupole, Buncher, Linear Accelerator, Linac, Beam Injector
JOURNAL NAME:
Journal of Electromagnetic Analysis and Applications,
Vol.15 No.1,
January
20,
2023
ABSTRACT: The Radio Frequency Quadrupole (RFQ) accelerator invented by Kapchinskii and Tepliakov can focus, bunch, and accelerate charged-particle beams simultaneously. Typically, it operates at frequencies up to 500 MHz, for low particle velocities (β ). The first attempt to design cylindrical RFQ for electrons in the GHz region was done using 3 GHz at Frascati in 1990. In this paper, an analytical approximation of the electromagnetic field is given, and linearized in the beam region for a rectangular Electron Radio Frequency Quadrupole (ERFQ). The differences between the proton-RFQ and the electron-RFQ are discussed. Then, it will be shown that contrary to the quadrupoles for protons or heavy-ions, the ERFQ is suited for electron velocities in the range 0.5 - 0.7 c, and possible applications are given. Finally, it is illustrated, with numerical field computations that this approach gives sufficient accuracy at 10 GHz.