Process for producing hollow bodies for resonators


High-frequency resonators, which comprise a plurality of hollow bodies, are especially being utilised in particle accelerators that use electric and / or magnetic fields for accelerating charged particles to high energies. Conventional superconducting resonators are usually made of polycrystalline niobium-tin material. The grain boundaries in the chemical treatment reduce the quality of the inner surface and thus the accelerating field intensity. The production of a single crystal-resonator (made of a material without grain boundaries, making its surface smooth as a mirror after pickling) is a promising step towards better performance.

Problems & Innovation

The industry is currently not capable of delivering niobium-single crystals of sufficient size. This invention shows that it is possible to shape the existing single crystals into a suitable form without destroying them. In addition, the single crystals grow together during the electron beam welding, taking the crystal orientations in to consideration.
A method for manufacturing unicellular and multicellular resonators made of niobium single crystals has been developed and tested. The required technical progress for this purpose is now protected by patents and is available for industrial applications.
In the patented process, the resonators are built from the niobium single crystal. This material does not have grain boundaries and thus has a surface as smooth as a mirror after pickling.


  • Defect-free crystal structure
  • The compounds of the hollow body do not cause any loss of tension
  • The single crystals grow together during electron beam welding