Mechanical studies of the multi-gap spoke cavity for European project HIPPI

Within the HIPPI (high intensity pulsed proton injector) project, supported by the 6th PCRD (framework programme for research and development) of the European Union, the German research centre Forschungszentrum Juelich proposed a multi-spoke H-cavity for the intermediate energy section (β 0.5) of high power proton linear accelerators. The IPN Orsay is associated with FZ Juelich for the prototype design, and before that, all preliminary mechanical studies. A triple-spoke superconducting cavity has a more complicated geometry, compared to the same beta elliptical cavity. As a consequence the design requires some sophisticated tools, like the CAD (computer aided design) code CATIA. In addition, in order to solve the specific mechanical problems imposed by external constraints, a sophisticated mechanical simulation tool CAST3M (Calcul et Analyse de Structure et Thermique par la methode des Elements Finis) is used [H. Gassot, in: Proceedings of the 8th European Particle Accelerator Conference, June 2002, Paris, ]. But no commercial modeling/FEA exchange software exists between CATIA and CAST3M, so the first investigation consisted in the development of a dedicated program for this purpose. The mechanical behaviour of the triple spoke cavity in static and dynamic regime was studied with these codes. The results are presented and discussed in this report