Manufacturing weld-free high-frequency resonators


Existing weak spots in manufacturing high-frequency resonators with weld seams are to be avoided with the help of this invention. On that point, a procedure for the manufacture of weld-less RF resonators has been developed and an appropriate facility has been designed and built.


So far for the most part, welded high-frequency resonators have been used. Although welded resonators have proved successful in service, it is still desirable to avoid welding at least at critical points.
For one thing, a seamless resonator is not exposed to the risk of contaminating the weld seams. This means that statistically speaking, it is expected to perform better than a welded resonator regarding a series. And for another thing, manufacturing costs can be reduced especially in larger series.


Some new technical and constructive ideas have been developed and utilised for the procedure and the facility. The multicell superconducting resonators built through hydroforming are worldwide unique.


  • This method is mainly needed for components of accelerators with the SCRF technology in order to achieve extremely high accelerating fields and to minimize the manufacturing costs.
  • An accelerating field of about 42 MV/m has been achieved with such a resonator made from a single cell - this is the highest value for TESLA cells. A 9-cell XFEL - resonator has been built. The accelerating field exceeds the XFEL requirements by far.
  • A reduction of the manufacturing costs is possible for larger series.

Development status

The method has been tested and utilised at DESY. The hydraulic manufacturing of the resonators can be gradually or continuously regulated through a newly developed computerised control system.