LINAC2026 - 33rd Linear Accelerator Conference

Development of a Real-Time Cavity Simulator for Automated Lorentz Force Detuning Compensation Studies of the ITN Cryomodule at KEK

Not scheduled

2h

Daejeon Convention Center

Poster Presentation MC4.A04: Low level RF Poster Session

Speaker

Dr Rishabh Bajpai (High Energy Accelerator Research Organization)

Description

At KEK, an International Linear Collider prototype cryomodule with eight TESLA-type cavities is under development. The cryomodule will operate in pulsed mode at 5 Hz. During RF operation, electromagnetic forces mechanically deform the cavity structure, shifting the resonance frequency through Lorentz Force Detuning (LFD).
A common method for LFD compensation is feedforward control using a piezo actuator driven by a half-sine waveform to restore resonance during the flat-top. Effective compensation requires optimization of waveform amplitude, frequency, DC offset, and phase relative to the RF pulse. Manual tuning is feasible for a small number of cavities but is time-consuming and difficult to scale.
To address this, an automated LFD compensation algorithm will be implemented on a Red Pitaya FPGA. However, validation of the tuner piezo controller at KEK is limited by the lack of testing capabilities with an actual SRF cavity and the tuner. To enable continued R&D, a cavity simulator with electromagnetic and mechanical models was developed as a substitute for the real cavity. This contribution presents the details of the cavity simulator and the status of automated LFD compensation.