Dynamic Performance Research Of Key Support Systems For FELs

Shanghai Soft X-ray FEL (SXFEL) and the Dalian Coherent Light Sourceproject (DCLS) are significant national science and technology infrastructure. Theelectron beam stability is one of the most important factors that influence theproperties of FEL. The increasing demands of beam position stability result in thehigher position stability requirement for the FEL key parts such as undulator andquadruple magnet. Since the mechanical support system for the FEL providessupporting, location and position adjustment, the high mechanical stability of thesupports is indirectly expected. This work focuses on the research of the dynamicperformance of mechanical supports for Beam Based Alignment (BBA) and chicaneby model experiments, vibration test and Finite-element (FE) calculations.According to the basic principle of mechanical vibration, support systems thatcan be equivalent to single degree of freedom have a certain amplified effect onground vibration. To develop support systems for BBA which have good positionstability and small ground vibration amplification ratio, this paper has researched thedynamic performance of the designed three different kinds of mechanical supports forBBA by modal and vibration experiments, and analyzed the influence of differentmaterials, different structures and different connection methods on mechanicalstability. Due to the conclusions above，engineering design of the support for BBA hasdetermined. Model experiments, vibration tests and FE calculations have been carriedout to analyze the prototype’s dynamic performance, showed inherent frequency80Hzand vibration ratio between the peak of quadruple and ground about1, which illustrategood vibration properties.Correct the grouting connection model in finite element analysis based on modaltest results of BBA platforms. Employ same methods to FE calculate mechanicaldeformation and modal properties. Small total deformation and high inherent frequency have been obtained, which demonstrate the feasibility of the engineeringdesign.This paper analyzed the main factors that influence mechanical stability, givenmeasures to enhance the stability of the support systems, which is very significant forsupport systems’design in FELfacilities.