S.K. Sharma, C.J. Spataro
BNL, Upton, New York, USA
The designs of various girder support systems were reviewed recently in a MEDSI School tutorial*. A comparison of their horizontal transmissibility values in (2-100) Hz band showed that the NSLS-II girder support system had a lower horizontal transmissibility despite its first natural frequency being the lowest (~30 Hz). Detailed vibration tests and FE analyses have been performed to understand this anomaly and to assess the role of viscoelastic damping pads underneath the NSLS-II girders. The analyses were extended to include harmonic response to model viscoelastic properties and random vibrations to obtain relative motions between the magnets. The results of these new tests and FE analyses are discussed in this paper. *S. Sharma, "Storage Ring Girder Issues for Low Emittance Storage Rings", Tutorial, Medsi School 2, Grenoble, France, October 2-25, 2019.
F. Khan, D. Crivelli, J.H. Kelly, A. Male
DLS, Oxfordshire, United Kingdom
Vibration in beamline optics can degrade the quality of experiments: the resulting movement of a mirror increases the x-ray beam position uncertainty, and introduces flux variations at the sample. This is normally dealt with by averaging data collection over longer periods of time, by slowing down the data acquisition rates, or by accepting lower quality / blurred images. With the development of faster camera technology and smaller beam sizes in next generation synchrotron upgrades, older optics designs can become less suitable, but still very expensive to redesign. Mechanically, mirror actuation systems need to be a balance between repeatability of motion and stability. This normally leads to designs that are ’soft’ and have resonant modes at a relatively low frequency, which can be easily excited by external disturbances such as ground vibration and local noise. In ultra-high vacuum applications the damping is naturally very low, and the amplification of vibration at resonance tends to be very high. At Diamond we designed a process for passively damping beamline mirror optics. First, we analyse the mirror’s vibration modes using experimental modal analysis; we then determine the tuned mass damper parameters using mathematical and dynamic models. Finally, we design a flexure-based metal tuned mass damper which relies on eddy current damping through magnets and a conductor plate. The tuned mass damper can be retrofitted to existing optics using a clamping system that requires no modification to the existing system. In this conference paper we show a case study on a mirror optic on Diamond Light Source’s small molecule single crystal diffraction beamline, I19.
Right click on video for Picture-in-Picture mode or Full screen display.
R.H. Liu, H.Y. He, Z.Y. Ke, L. Liu, X.J. Nie, C.J. Ning, A.X. Wang, Y.J. Yu, D.H. Zhu
IHEP CSNS, Guangdong Province, People’s Republic of China
L. Kang, J.S. Zhang
IHEP, Beijing, People’s Republic of China
G.Y. Wang
Institute of High Energy Physics, CAS, Guangdong, People’s Republic of China
Funding:National Natural Science Foundation of China 11905231 With the development of high-energy synchrotron radiation light source with high energy, high brightness, low emittance and nano-scale light spot, accelerators and beamline stations have higher requirements for the stability of the system, and active vibration isolation technology has been paid more and more attention. It has become the key technology for the development of major scientific devices (such as high-energy synchrotron radiation light source, free electron laser, etc.) in the future. In this paper, an active vibration control system driven by piezoelectric ceramic actuator with strong adaptability is designed. NI Compact-RIO real-time control system and Fx-LMS adaptive filter control algorithm are used for the active vibration control system. The identification method of input and output channels and the active control module are simulated by MATLAB. And an active vibration control system based on a parallel 6-DOF platform was built for experimental verification. The experimental results show that the designed active vibration control system has a good control effect for low-frequency micro-vibration.
Tighter specifications in synchrotron instrumentation development force the design engineers more and more often to choose a mechatronics design approach. This includes actively controlled systems that need to be properly designed. The new Nano Active Stabilization System (NASS) for the ESRF beamline ID31 was designed with such an approach. We chose a multi-body design modelling approach for the development of the NASS end-station. Significance of such models depend strongly on its input and consideration of the right stiffness of the system’s components and subsystems. For that matter, we considered sub-components in the multi-body model as reduced order flexible bodies representing the component’s modal behaviour with reduced mass and stiffness matrices obtained from finite element analysis (FEA) models. These matrices were created from FEA models via modal reduction techniques, more specifically the component mode synthesis (CMS). This makes this design approach a combined multibody-FEA technique. We validated the technique with a test bench that confirmed the good modelling capabilities using reduced order flexible body models obtained from FEA for an amplified piezoelectric actuator (APA).
