LCSE

LCSE

Insert of the test facility for measuring thermal conductivity

The task of LCSE is to master cryogenics technology applied to superconducting magnets, accelerating cavities, physics detectors (cryogenic target systems, calorimeters), and the production and distribution of liquid helium.

For its own developments, and to meet project needs for development and testing, the laboratory designs, builds, and operates several test and characterization stations to determine the mechanical, thermal (see figure), and electrical properties of complete cryogenic subassemblies (such as magnets within cryostats, cryomodules, …), or their basic components (coil cold mass, RF cavities, instrumentation). These stations of various types and sizes use low-temperature refrigeration systems, such as refrigerators or cryogenerators, using the following fluids: helium I and II, nitrogen, argon, neon, or hydrogen.

More specific R&D activities are being carried out on the study and improvement of low-temperature heat transfer systems (helium II in porous media, PHP (pulsating heat pipes) with different gases at cryogenic temperatures), on two-phase flows (thermosiphon with helium I or nitrogen), on the thermohydraulics during magnet "quench", and on the development of cryogenic targets in liquid or solid hydrogen.

At the end of 2020, laboratory staff consisted of 16 engineers, two doctoral students, and six technicians.

#736 - Last update : 07/05 2023

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CELLO refrigerator for the JT-60SA test facility : The JT-60SA cold test facility was designed and constructed to validate the 18 superconducting magnets that will be installed on the JT-60SA tokamak at Naka in Japan. The “CELLO” HELIAL liquefier/refrigerator originally attached to the station used to test prototype magnets for the LHC has been moved. It now provides cooling for the JT-60SA test station and produces the liquid helium necessary for testing the magnets at nominal current. Its cooling power is around 500 W at 4.

Chemistry laboratory and clean-room (Orme des Merisiers) : Chemistry laboratory Surface treatments for superconducting accelerator cavities. 1 fume hood for the treatment of cavities. 1 ultrasonic degreasing station (60 l). Ultra-pure water production plant with a capacity of 3 m3. 35 m2 ISO class 5 clean-room Assembly of cavities following high pressure rinsing.

Cryo/HF Supratech platform : The Cryo/HF Supratech station has cryogenic and hyper-frequency equipments[PO1] that can be used to develop the key subassemblies of superconducting accelerators such as superconducting cavities, power couplers and complete accelerator modules (e.g. cryomodules).

CRYOMECHA - Measurement of the Thermal Conductivity of Insulators and Conductors (MECTIX) : Context Thermal conductivity measurements on samples (Φ ≈ 30 mm) of insulating or conducting material by using the differential or integral method.

CRYOMECHA - Mechanical test laboratory : The mechanical test laboratory can perform measurements at 300 K and cryogenic temperatures: 77 K (liquid nitrogen) and 4.2 K (liquid helium), for determining mechanical characteristics (modulus of elasticity, elastic limit, breaking load, rupture elongation, and fragility) of metals or composites (synthetic composites or highly anisotropic compounds such as superconductors), and the behavior of complete assemblies under flexion, traction, compression or slippage.

CRYOMECHA - Mechanical test laboratory : Context Mechanical tests at room temperature or cryogenic temperature: 77 K (liquid nitrogen) and 4.2 K (liquid helium). Determination of the mechanical characteristics (elasticity modulus, elastic limit, breaking load and stretch, fragility) of metal and composite materials, study of assembly behavior (bending, traction, compression and slippage).

CRYOPULSE : Horizontal cryostat 6 m in length for characterizing flows and thermal performance by means of temperature and pressure measurements in cryogenic pulsating heat pipes up to 4 m in length. Power available for the loop: 200 W.

Diagnostics, vacuum and assembly laboratory (DIVA) : The laboratory is responsible for vacuum measurement, for research into the desorption of materials and the development of ultra-high vacuum techniques (assemblies and tests). Its equipment includes: ? An ultra-high vacuum oven that can reach temperatures up to 1200 °C at 10-6 Pa, with temperature uniformity at 900°C of ± 3°C. ? A desorption measurement bench for qualifying materials and developing cleaning procedures necessary for ultra-high vacuums.

Double bain : A cryostat using the Claudet double bath principle, for carrying out thermal studies on static pressurized superfluid helium up to a power of 10 W at 1.8 K with a maximum pressure of 1.5 bar(a) in a test volume of dimensions of diameter 200 mm x height 200 mm

Hélial 4003 liquefier - refrigerator used with the W-7X test station : The W7-X test facility was used to validate the 70 superconducting magnets installed on the European magnetic confinement fusion research machine, the Wendelstein 7-X stellarator. This test facility has two cryostats with a usable diameter of 5 m and a usable height of 4.1 m. The “4003” HELIAL liquefier, which has a capacity of around 200 W at 4.2 K, provides the cooling power for the test facility.

Hélial 4008 liquefier in the liquefaction station : In 2015, 131,000 liters of liquid helium were delivered to different laboratories on the CEA Saclay site and the surrounding area. The “4008” HELIAL liquefier, which has a capacity of around 70 l/hour, produces liquid helium in two tanks of 6,000 and 18,000 liters, giving flexibility for management of the liquefaction station.

Hélial 4012 Liquefier-Cooler connected to Supratech station : Liquefier production is around 170 or 70 litre/hour with or without nitrogen pre-cooling. A helium compressor 80g/s (1600 m3/h) and an Air Liquide cold box make up the liquefier. Its cooling power is around 80 Watt at 1.8 K

Insulation laboratory : Context Project technical support for insulation and winding of superconducting magnets. The insulation laboratory is equipped with several technical means allowing for example to : design small coils, impregnate prototypes or characterization specimens, prepare superconducting cables before characterization via the dissolution of aluminum or copper, process resins and chemicals, perform characterizations at room temperature.

Insulation/impregnation laboratory : The insulation/impregnation laboratory provides technical support for SACM’s projects on insulation for superconducting magnets and their winding: production of small coils, impregnation of prototypes or characterization samples, preparation of superconducting cables prior to characterization by dissolving aluminum or copper, use of resins and chemicals, room temperature characterizations (calorimeter, tensiometer, rheometer, pycnometer), etc.

Measurement of Kapitza resistance and thermal conductivity : Cell for measuring Kapitza resistance and thermal conductivity in superfluid helium between 1.7 K and 2.1 K on thin samples (0.5 mm max), up to 80 mm in diameter.

Measurements in pressurized superfluid helium at 1 atm : Double bath NED cryostat. Volume at 1.8 K: Diameter 250 mm x Height 300 mm. Double bath Th0 cryostat. Volume at 1.8 K: Diameter 200 mm x Height 500 mm.

Mechanical workshop : The mechanical workshop is more a prototype workshop than a production workshop. It is available for urging needs of experiments and in case of modification requirements. It makes available : 5 turning lathes, 5 millers, 1 reaming machine, 1 flat surface grinder, and other machines like drilling machines, sawing machines …

The SEHT test facility : The SEHT facility, which was created to generate an 8 T magnetic field in a large volume, uses a solenoid winding with an NbTi conductor assembled from double pancake coils cooled in a superfluid helium bath at 1.8 K and 1.2 bar absolute. The SEHT solenoid is a reconditioned superconducting coil previously used in the 35 T hybrid magnet at LNCMI in Grenoble.

Thermautonome : Context Characterization of single phase and two-phase flows (by measurements of pressure drop and wall temperature) along a vertical test section (h = 30 cm), in the ranges of temperature and pressure: 3 K ≤ T ≤ 30 K, P ≤ 3 bars.

THERMAUTONOME : A circulation loop with recondensation by means of a cryogenerator, for characterizing single phase and two-phase flows by measuring pressure drop, and wall temperature increase along the wall of a 30 cm vertical test section. Cryogenerator: 1.5 W at 4.2 K. Pressure: from a few mbar to 3 bar. Temperature: from 3 K to 30 K. Max Power in the loop: 4 W at 10 K.

Thermosiphon test bench : Context Characterization of single phase and two-phase flows (by measurements of mass flow rate, volume ratio, pressure drop and wall temperature) along a vertical test section (h = 1.2 m) and a horizontal test section (Φ = 0.4 m) at the temperatures of liquid helium and nitrogen. The station offers a large versatility in the geometry of the cooling loop.

Ultra high vacuum laboratory : The ultra high vacuum laboratory takes charge of the vacuum calculations for accelerators, the research about material desorption and the development in ultra high vacuum techniques and vacuum theory. Ultra high vacuum oven : 1200°C, 10-6 Pa.

Winding laboratory : The winding laboratory, used for making small prototype coils, has a large capacity winding machine with a vertical axis, a winding machine with a horizontal axis and a winding machine with a vertical axis and a horizontal axis for making more complex coil geometries. Each of these machines has a brake to control the mechanical tension on the conductor. There is a 1500 metric tonne hydraulic press with a heating system for heating under mechanical stress (polymerization, bonding, etc.).

Division of accelerators, cryogenics and magnetism

Institute of research into the fundamental laws of the Universe