Proton Linac Development Division
Design and Development of Components of 325 MHz Single Spoke Resonator (SSR)

Superconducting single spoke resonators (SSR) are proposed to be used to accelerate proton beam in the low energy section of the IFSR linac. Based on physics design data, engineering design of a 325 MHz spoke resonator with β = 0.11 (SR011) was carried out. Fig. 1 shows the stress pattern whereas Fig. 2 the deformation pattern. The engineering design of SR011 include designing of stiffener rings for structural stability, studies for Lorentz force detuning (LFD) and helium pressure fluctuations (df/dP). Since, major components of cavity are manufactured by deep drawing process therefore, FEA based forming analysis of components were carried out. Design analyses for forming of end wall (Fig. 3), spoke (Fig. 4), shell pull out for vacuum and power coupler port and spoke to shell collar were performed. During simulations, tool geometry, binding force, blank size etc. were varied to minimize thinning, wrinkling, developed stress & strain etc. on formed component. Spring back during forming of components were evaluated and tried to minimize it by modifying tool geometry. Based on forming analysis results, detailed fabrication drawings for tooling were developed and die and punch for cavity components were fabricated. Using developed tooling, forming of SR011 cavity components was carried out. Fig. 5 and Fig. 6 shows die & punch and formed component of end wall respectively. Similarly, Fig. 7 formed component of spoke respectively. Forming of all components came out to be wrinkle and tear free. In addition to this, die and punches for spoke to shell collar (Fig. 8) and shell were also fabricated and forming trials were carried out successfully.

Fig.1: Stress pattern for SSR cavity
Fig.2: Deformation pattern for SSR cavity
Fig.3: Thinning (%) after forming simulation of End wall
Fig.4: Thinning (%) after forming simulation of spoke
Fig.5: Fabricated die & punch for end wall loaded on 120 ton hydraulic press
Fig.6: Formed end wall of SR011 in aluminium
Fig.7: Formed spoke of SR011 in aluminium
Fig.8: Formed spoke to shell collar component of SR011 in aluminium

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