Horizontal cryostat for cavity tests
Horizontal cryostat for cavity tests

Cylindrical cryostat CRYHOLAB with its rectangular satellite

Context

High power RF characterization tests of superconducting cavities equipped with their power coupler and tuning system, at low temperature down to 1.8 K, in conditions close to their final use in an accelerator.

A cylindrical horizontal cryostat (CRYHOLAB) shielded against earth magnetic field allows one to fully characterize superconducting cavities feeded with high power RF (thermal budget, Lorentz force detuning, microphonics, etc). Its dimensions are l = 1.5 m long and Φ = 0.7 m diameter. A satellite of dimension l = 1.7 m long, w = 0.8 m large and h = 0.7 m high can be added in case the cavity does not fit in the cylinder.


 

 
Horizontal cryostat for cavity tests

High power RF platform (704 MHz and 1.3 MHz)

 

Technical means

  • Liquid Helium cooling: a main refrigerator unit providing up to 30 l/h to the horizontal cryostat, allowing one to provide helium at 4.2 K or 1.8 K by pumping on the helium bath.
  • High power RF platform equipped with:
    • two klystrons (PPeak = 1.1 MW, f = 704 MHz), providing pulses with duration T ≤ 3.6 ms at f = 14 Hz,
    • one klystron (PPeak = 2 MW, f = 1.3 GHz), providing with duration T ≤ 1 ms at f = 10 Hz,
    • possibility to install RF source provided by client.

Full RF control and safety chain is provided for existing power sources.

 

Achievements, related projects

  • XFEL, SPL, ESS fully equipped prototype elliptical cavities qualification,
  • IFMIF half-wave fully equipped cavity qualification.
 
Horizontal cryostat for cavity tests

Cylindrical cryostat CRYHOLAB

 

 

Technical steps, expertise

  • Mounting of the cavity equipped with its tuner in the horizontal cryostat,
  • Mounting of the power coupler to the cavity, connection to pumping lines and RF power lines,
  • Leak checks and low power RF checks at room temperature,
  • Cooling down to 4.2 and/or 1.8 K, with fast ramps (3 K/min) from 150 to 50 K,
  • Control of cavity frequency, field ramp in cavity by injecting increasing RF power and concurrent measurement of quality factor deduced from Pi, Pt, Pref,
  • Control of tuning system capabilities in terms of frequency range, hysteresis, etc.
 

Contact: 

 

Last update : 06/05 2018 (3948)

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