Study of Lorentz force detuning and its compensation in superconducting radiofrequency cavity: A review

Abstract

Abstract Modern days accelerators-based on superconducting technologies are increasingly being used to accelerate the charge particles. SCRF (Superconducting Radiofrequency) cavities, made up of superconducting material, are highly sensitive to any perturbation because of high-quality factor, which provides narrow resonance bandwidth and hence, its operation becomes challenging. These perturbations are due to either internal or external sources during an actual operating condition of the SCRF cavity. The internal source is radiation pressure acting on the cavity wall due to an electromagnetic field also known as Lorentz force detuning (LFD) and external sources are microphonics due to external vibrations and pressure fluctuations caused by the cryogenic system. These sources may degrade the performance of the SCRF cavity in an accelerator. Therefore, investigation and compensation of these sources are necessary for smooth operation of superconducting accelerators. Lorentz force detuning is a major issue for superconducting cavities at higher voltage gradients of the accelerator. The focus of this paper is to review Lorentz force detuning and its behaviour in various superconducting cavities. It also discussed different finite element tools used to estimate the LFD and different techniques to compensate for the LFD effect in the SCRF cavity.