Structural analysis of quarter-wave resonators in IMP

The taper-shaped superconducting quarter wave resonators with frequency of 80.5 MHz, β of 0.041 and 0.085 have been pre-researched. The radio frequency (RF) design of the cavities has been completed, and the structural design is also an important aspect which will be discussed in the following. The frequency shift caused by the etching effects of the surface treatment, the helium bath pressure and the Lorentz force, and the mechanical modes caused by the microphonic excitation have been analyzed. The results show that the frequency variation from the Lorentz force is not serious and stiffening rings are explored aimed at decreasing the deformation brought by the helium pressure and microphonic excitation. (authors)