Vertical electropolishing cabinet

Vertical electropolishing station


Chemical and electrochemical treatment of elliptical cavities (maximum cavity height: 1.8 m and maximum mass: 200 kg).

This station allows one to perform chemical or electrochemical polishing of the internal surface of niobium cavities.


Vertical electropolishing cabinet


Technical means

  • Power supply: 20 V, 1200 A,
  • Acid flow rate: 40 l / min,
  • 300 l acid tank,
  • Pipe and pumps made of PFA material, teflon coating of the acid tank,
  • Cavity-station interface with rotating flanges to ensure the sealing of the connections,  
  • Cavities are handled by a crane with specific tooling for each cavity. The station is also equipped with a table for horizontally inserting the cathodes.

Electropolishing cycles are automated.


The station is located in a Non-Explosive Atmosphere Area. Measures are taken to limit the various sources of risk:

  • Hydrogen detection via 2 detectors with automated shut-off of the generator and ventilation of the treatment booth which ensures a low concentration of process gases in the event of a leak,
  • Control of the acid temperature (via an 18 kW power cooling unit connected to a heat exchanger: 156 m PFA pipe) to minimize the risks associated with exothermic reactions (the working temperature is below 20 °).

Additional facilities: acid storage room, gas extractor-washer which ensures the ventilation of workstations, acid liquid waste collection and treatment system, pure and ultrapure water treatment plant (resistivity : 17.7-17.9 MΩ.cm).


Achievements, related projects

  •  Treatment performed to increase the surface quality of superconducting cavities, in the framework of the XFEL and ESS projects,
  •  R&D experiments on vertical electropolishing.

Technical steps, expertise

  • Vertical positioning of the cavity,           
  • Chemical or electrochemical treatment (automated cycle),
  • Rinsing with ultrapure water (resistivity: 17.9 MΩ.cm) and extraction of acids and polluted water.



Last update : 08/02 2017 (3950)

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