CW OPERATION OF SUPERCONDUCTING TESLA CAVITIES

Several recently proposed superconducting linacs are designed to operate in CW mode. The TELSA technology, which they are based upon, was originally developed for pulsed mode. In order to demonstrate the feasibility of CW mode with TESLA technology, BESSY has built the HoBiCaT test facility [1]. The main issues of CW operation were examined and solutions are shown on the following topics: Limits of heat conduction in the Helium vessel, gas dynamics in the two phase line, layout of a CW cryo module, heating of HOM couplers, CW operation of the main RF coupler, choice of helium bath temperature, pressure stability of the helium bath and microphonics and their compensation.