# Study on high order modes in a beta=0.09 srf hwr cavity for 100 ma proton acceleration

## TL;DR

This paper investigates high order modes in a superconducting HWR cavity designed for 100 mA proton acceleration, analyzing HOM-induced power and the effects of manufacturing errors to improve high-current beam stability.

## Contribution

It provides the first detailed analysis of HOM-induced power and coherent excitation risks in a beta=0.09 HWR cavity for 100 mA proton beams, combining time domain and frequency domain methods.

## Key findings

- HOM-induced power was quantified for 100 mA beam currents.
- Incoherent beam energy loss was calculated using two different methods.
- The study assessed the impact of manufacturing errors on cavity stability.

## Abstract

There's presently a growing demand for cw high current proton and deuteron linear accelerators based on superconducting technology to better support various fields of science. Up to now, high order modes (HOMs) studies induced by ion beams with current higher than 10 mA and even 100 mA accelerated by low beta non-elliptical Superconducting rf (SRF) cavities are very few. Peking University has recently designed and fabricated a beta=0.09 162.5 MHz HWR cavity to study the key physics problems in accelerating beam with current of about 100mA. This paper focuses on the study of the HOM-induced power in this cavity. The incoherent beam energy loss induced by 100 mA beam through the HWR SRF cavity were obtained from both time domain solver and frequency domain eigenmodes spectrum method. We also analysed the possibility of coherent excitation of this cavity considering of manufacture errors.

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Source: https://tomesphere.com/paper/1702.03636