An FEA Investigation of the Vibration Response of the BEATS Detector Stage

Abstract

The Synchrotron-light for Experimental Science and Application in the Middle East (SESAME) facility is in the process of designing, procuring, and installing a new beamline for tomography (BEATS). The BEATS experimental hutch, hosting sample and detectors, will be located 43 m away from the undulator in the synchrotron ring. Noise in the form of vibration originating from different sources transferred to the detector stage can be a source of poor image quality thus it is important that the detector stage is analysed for its vibration transmission properties. In this study, the result of a three-dimensional random vibration analysis using Finite Element Analysis (FEA) for the detector stage is presented which leads to an estimate of the severity of the vibrations. The random vibration source is that of the ground which was measured exactly where the detector stage will be mounted. The random vibration analysis is conducted in two stages; the modal frequencies of the structure are calculated, thereafter, the random vibration analysis is conducted and the response power spectrum density (PSD) of the structure is calculated along with the root mean square (RMS) displacement values. Since the beamline BEATS is under installation, an existing structure installed at beamline ID28 of the European Synchrotron Radiation Facility (ESRF) was used to validate the model. The model used on the ID28 structure deviated from the experimental results on modal analysis by 2% - 4% on random vibration analysis. This suggested that the model is valid. The analysis as applied to the BEATS detector stage design predicts that the RMS displacement values are less than the pixel size of the detector which is 1 μm. Thus, the structure is sufficiently engineered to moderate the floor vibrations.