Vertical cryostats for cavity tests (CEA)
Low power RF characterization tests of superconducting cavities at low temperature down to T = 1.8 K. Two buried vertical cryostats (CV1 and CV2) shielded against earth magnetic field allow one to measure accelerating gradient and surface resistance of superconducting cavities. They can accommodate:
- R&D single cell cavities up to Φ = 0.45 m diameter and l = 1 m long in CV1,
- cavities for accelerator projects (R&D, prototypes and series) up to Φ = 0.7 m diameter and l = 1.9 m long in CV2.
Horizontal cryostats for cavity tests (CEA)
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.
- 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 pulses with duration T ≤ 1 ms at f = 10 Hz.
Cryomodule test station (CEA)
The 6.6 m long cryomodule houses 4 superconducting cavities operating at 2 K, each powered by an RF power coupler transmitting up to 1.1 MW of peak power. 4 types of diagnostics to provide an estimate of the intensity of the beam, a measurement of the position of the center of gravity of the beam, an estimate of the „quality” of the beam in terms of spatial distribution and energy and an estimate of the purity of the particles that compose the beam.
SM18 SC cavity test area (CERN)
The SRF section is in charge of superconducting RF related activities within the RF group. In particular this comprises:
- Closely collaborate with specialist engineering and technical groups in cavity mechanical design, cavity fabrication, cavity surface preparation and treatments,
- Study the properties of superconducting materials in RF fields and contribute to the global effort of improving SRF cavity performance and reliability,
- Carry out RF testing and measurement of superconducting cavities throughout the production process and perform the final testing of bare cavities at cryogenic temperatures.
Cryogenic test facilities and tests stands (CNRS)
The cryogenic infrastructure, which includes two tests areas respectively located in the buildings 103 and 106 at IPNO, consist of the following equipment’s:
- A helium liquefier (Linde L70),>/li>
- Helium pumping systems for tests in superfluid helium,
- Gaseous helium recovery for recycling after use,
- Two cryogenic test facilities,
- Three test stands with vertical cryostats (ID: 800 mm, 350 mm and 125 mm),
- Several cryogenic inserts for cavity testing, material and component characterization at low temperature,
- A facility for calibration of cryogenic thermometers in the range 1.6 K -300 K
Vertical cavity test stands (DESY)
At DESY the inserts are adaptive for different cavity types, and usually have an adjustable RF antenna. Typical measurements start with the accelerating gradient as a function of the loaded quality factor (eq. to cryogenic losses). More sophisticated are RF measurements in the different pass-band modes, the temperature map or a second-sound measurement to locate quenches. Sensors checking radiation caused by field emission and magnetic flux complete the picture.