Design Guideline for Minimizing Space-Charge-Induced Emittance Growth

TL;DR

This paper proposes a new design guideline for minimizing space-charge-induced emittance growth in low energy, high intensity linacs by maintaining a specific emittance ratio, demonstrated through RFQ accelerator comparisons.

Contribution

It introduces an alternative to the Equipartitioning Principle, focusing on maintaining a balanced emittance ratio to reduce emittance growth in accelerator design.

Findings

The new guideline effectively reduces emittance growth in RFQ accelerators.

Comparison shows advantages over traditional equipartitioning approach.

Maintaining emittance ratio around one improves beam quality.

Abstract

Space-charge-induced emittance growth is a big con-cern for designing low energy and high intensity linacs. The Equipartitioning Principle was introduced to mini-mize space-charge-induced emittance growth by remov-ing free energy between the transverse and longitudinal degrees of freedom. In this study, a different design guide-line is being proposed. It suggests to hold the ratio of longitudinal emittance to transverse emittance around one and take advantage of low emittance transfer for minimizing emittance growth. Using a high intensity RFQ accelerator as an example, a comparison between the two design methods has been made.