Design approach for modern high-current, radio-frequency quadrupole accelerators with low emittance transfer

TL;DR

This paper proposes a novel RFQ design guideline to optimize high-current beam quality and transmission by controlling emittance transfer, integrating it with existing design methods for improved accelerator performance.

Contribution

It introduces an emittance ratio guideline (el/et=1.0) to prevent beam instabilities, combined with the BABBLE/NFSP design method for high-current RFQ accelerators.

Findings

Achieved high beam transmission with low emittance transfer.

Designed RFQ accelerators with short structure length and high beam quality.

Validated the effectiveness of the el/et=1.0 guideline in simulations.

Abstract

Radio Frequency Quadrupole (RFQ) accelerators often need to face the challenges of space charge effects from high beam currents. This study investigated how to reach RFQ beam dynamics designs with not only high beam transmission and short structure length but also high beam quality simultaneously. To avoid beam instabilities induced by emittance transfer, a so-called el/et (ratio of the longitudinal and transverse emittances) = 1.0 design guideline is being proposed. The application of this design guideline integrated with the BABBLE/NFSP design method for a high current, high frequency, high injection energy RFQ accelerator is described.