Thermal study of HOM couplers for superconducting RF cavities

The thermal behaviour of a “fish hook” type HOM coupler for superconducting RF Cavities is analyzed by numerical simulation using a 3D finite element based code for both CW (rings, recirculating linacs) and pulsed (s.c. colliders studies like TESLA) accelerator types. Consequently, a thorough study of the thermal stability of this system is necessary in both transient and steady-state regimes. Numerical simulations, assuming anomalous losses at the end of the HOM inner conductor, were performed. The effects of the HOM coupler geometry and the materials thermal conductivity on the critical heat flux inducing the quench of the system are discussed