Scattering matrix simulations of fields and dispersion relations in superconducting cavities for XFEL and ILC

TL;DR

This paper presents a globalized scattering matrix method for efficient simulation of RF structures in superconducting cavities, enabling accurate field and dispersion relation calculations with fabrication error considerations.

Contribution

It introduces an efficient globalized scattering matrix technique for simulating large superconducting RF cavities, including realistic fabrication errors, without re-meshing the entire structure.

Findings

Accurate monopole mode fields and dispersion relations obtained.

Analytical approximations for shunt susceptance provided.

Method enables rapid electromagnetic simulations of complex structures.

Abstract

The globalised cascaded scattering matrix technique is a well proven, practical method that can be used to simulate large accelerating RF structures in which realistic fabrication errors to be incorporated in an efficient manner without the necessity to re-mesh the entire geometry. The globalised scattering matrix (GMS) technique allows one to obtain the scattering matrix for a structure. The method allows rapid e.m. field calculations to be obtained. Results are presented on monopole mode fields and dispersion relations calculated from direct and analytical methods. Analytical approximate results are also presented for the equivalent shunt susceptance of an iris loaded structure.