Effects of material properties on resonance frequency of a CESR-III type 500 MHz SRF cavity

A simulation that links the calculation of mechanical structure and of radio frequency electromagnetic field with the finite element code ANSYS/spl reg/ is employed in this study. Both efficiency and accuracy of the calculation are thus improved over those of the conventional computation that builds separate models with different codes for each computed domain because information related can be internally transferred between the different computation domains. The resonance frequency changes associated with mechanical properties of niobium are examined. The computed results indicate that the coefficient of thermal expansion significantly affects the shift in resonance frequency that occurs when the cavity is cooled from room temperature to liquid helium temperature. Young's modulus and Poisson's ratio have minor effects.