上海光源实验大厅地基振动规律及相干性分析

摘要

Multi-points synchronous measurement of random ground vibration of the experimental hall of SSRF has been done using high sensitivity velocity sensors. Results of analysis show that the amplitude of the random ground vibration of the hall changes periodically, and the 1-meter thick cement floor supported by piles has a good vibration isolation performance for the frequencies beyond 2 Hz. It is the first-time test of the coherence law of the random vibration transfer in the experimental hall of SSRF. Results of measurement show that the cross-correlation of the random vibration at the measurement points with 10-meter spacing is greater than 0.9 in the frequency range below 2.5 Hz. When the spacing exceeds 10m, the displacement deviation of the random vibration between two adjacent measurement points is greater than 50 nm, which exceeds 20%of the vibration amplitude in RMS. The test result of the coherence in the experimental hall of SSRF can be considered as a reference for the beamline isolation design.%利用高灵敏度速度传感器，对上海光源实验大厅地基的随机振动进行了多点同步测量。数据分析结果表明上海光源实验大厅地基随机振动幅值具有周期变化的规律，且在低频区2 Hz～10 Hz具有较好的隔振效果。首次在上海光源大厅内进行随机振动中传递的相干规律的测试，测试表明在上海光源实验大厅中，距离为10 m的测试点在2.5 Hz以内的随机振动的互相关大于0.9；距离超过10 m时，两点随机偏差大于50 nm，超过随机振动RMS振幅的20%。随机振动传递规律的分析，对同步辐射光学元件的隔振设计有一定的指导作用。