SRF cavity geometry optimization for the ILC with minimized surface e.m. fields and superior bandwidth

TL;DR

This paper presents a new cavity shape design for the ILC that reduces surface electromagnetic fields and improves bandwidth, enabling higher gradients and better performance compared to previous designs.

Contribution

The authors introduce the NLSF cavity shape, optimizing surface fields and bandwidth, offering a novel design for superconducting RF cavities in linear colliders.

Findings

Reduced surface electric and magnetic fields compared to previous designs

Enhanced bandwidth of the accelerating mode

Comparable or improved performance relative to existing cavity geometries

Abstract

The main linacs of the ILC consist of nine-cell cavities based on the TESLA design. In order to facilitate reaching higher gradients we have re-designed the cavity shape. This leads to a reduction, comparable to several current designs, in both the ratio of the surface electric field to the accelerating field (Es/Ea) and the magnetic field to the accelerating field (Bs/Ea). The bandwidth of the accelerating mode is also optimized. This new shape, which we refer to as the New Low Surface Field (NLSF) design, bears comparison with the Ichiro, Re-entrant and LSF designs.