He jishu (Jan 2022)
Finite element analysis and measurement of vibration responses of cryomodule 1.3 GHz superconducting accelerator
Abstract
BackgroundThe superconducting cryomodule used in Shanghai high repetition rate X-ray freedom-electron laser (XFEL) and extreme light facility (SHINE) requires strict control of the position jitter tolerance which generally does not exceed 10% of the beam size. The root mean square values of the cavities' transverse displacement in the cryomodule should not exceed 300 nm between 1 Hz and 100 Hz.PurposeThis study aims to obtain the random vibration responses of the cryomodule with different length of screw rods hanging at the ceiling through finite element analysis (FEA) and vibration test, to judge whether the stability requirement is met, and to provide a reference for the selection and optimization of the support structure.MethodsFirst of all, simplified model of the cryomodule was constructed by SOLID EDGE, and the ANSYS Workbench was employed for modal analysis to obtain the natural frequencies and vibration mode of the structure. Then, random responses of the cryomodule hanging at the ceiling were carried out through FEA and vibration measurement. The root mean square values of cavities' transverse vibration in 1 Hz ~ 100 Hz frequency band got by simulation and measurement were compared to determine the accuracy of the model and the stability of the cryomodule. Finally, the vibration data of the cryomodule's further operating environment was monitored to confirm the stability of the structure.ResultsThe simulation and measurement results are in good agreement, the screw elongation of 8 cm has no effect on the vibration responses of the cavities.ConclusionThe accuracy of the model simplification proposed in this study is verified by FEA simulation and on-site measurement. The root mean square values of the cavities' vibration measurement meet the stability requirement for 1.3 GHz superconducting accelerator.
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