Accelerators, Cryogenics and Magnetism Division (DACM)

The mission of the division of accelerators, cryogenics and magnetism is to develop and produce particle accelerators, ion sources, accelerator cavities, cryogenic systems and superconducting magnets for Irfu's scientific programs. For this, the DACM has extensive assembly, integration and testing facilities, ranging from winding and magnet assembly halls, to large clean rooms for accelerator systems and small test stations to characterize materials, to very large stations capable of testing complete assemblies.
Thanks to its advanced skills, the DACM ensures the prime contracting of accelerators or parts of accelerators such as Iphi, the design and prime contracting of accelerator magnets and magnets integrated into detection devices as well as associated cryogenic devices. Drawing on its skills, the DACM applies its technologies to other research fields such as energy with the JT-60SA tokamak or life sciences with the Iseult project magnet.
In order to ensure the conduct of large-scale projects, the DACM must develop the corresponding testing resources. Thus, it also conducts a strong R&D program that prepares the future of technologies to provide the necessary tools for advances in basic and applied research. It also designs and develops platforms and test stations as well as the production of cryogenic fluids used at Irfu.


   Access to DACM's website :


Head of division : Pierre Vedrine

Deputy : Christophe Mayri

#732 - Last update : 08/22 2023
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352 MHz RF platform : 352 MHz RF platform is equipped with: ? Two Thales TH2089B klystrons that can each deliver 1.3 MW of continuous RF power. ? One Thales TH2179A pulsed klystron with an in-built DTI Sigmaphi modulator with a peak power of 3 MW, which can deliver 240 kW of average RF power, with a pulse length of between 10 and 3600 μs and a frequency repetition of between 1 and 50 Hz. In particular these characteristics cover the useful cycle of the ESS (European Spallation Source).
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.
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). In the last three years, it has been used to test the 12 cavities and 12 cryomodules for SPIRAL2, the HIPPI power couplers (for the European EuCARD program and in collaboration with CERN) and the prototype cavities for the IFMIF and ESS projects.
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.
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.
DACM - past and futur projects : In the last three years, DACM has scored a number of successes: the injectors of SPIRAL2 and IFMIF have been tested in an operational situation in their bunkers inside the Synergium and have achieved their nominal performance. The 51 tons of superconducting material necessary for the ISEULT project were produced and 170 double pancakes were wound with the required accuracy. The development of innovative antennas for medical imaging has continued with success.
DACM - the missions : The expertise of the Department has also been deployed in support of work in associated fields including energy (materials studies for thermonuclear fusion as part of the IFMIF project, qualification of the coils of the Japanese JT-60SA Tokamak), life sciences (the ISEULT ultra high field magnetic resonance imager for NEUROSPIN) and light sources (SOLEIL and XFEL). DACM also provides management services for major large scale projects and develops the associated test systems.
DACM - the organisation of the division : DACM is division of the Institute of Research into the Fundamental Laws of the Universe (IRFU), of the CEA Physical Sciences Division (DSM). It is located on the Saclay center in the premises of the former National Laboratory Saturne, LNS, and the former Department of Instrumental Techniques of Elementary Particles, the STIPE. These premises have been renovated and gathered in a large platform called "Synergium" which occupies a total floor area of 25,000 m2.
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.
Ion Source Test Bench (BETSI) : Context Injector of light ion beam for ion source characterization, test of diagnostics and beam delivery for experiments.   The test bench is equipped with an ECR ion source connected to an accelerating column mounted on a compact high voltage platform biased up to 100 kV. A dedicated extraction system allows the production of mono-charged light ion beams (typically Hydrogen ions with 80% H+, 15% H2+ and 5% H3+).
ISO4 clean room : Context Assembly of cavities following high pressure rinsing. Positive pressure clean room partitioned into 3 different ISO classes: 7, 5 and 4.  
ISO5 clean room : Context Assembly of cavities following high pressure rinsing. Positive pressure clean room partitioned into 2 ISO classes (ISO class 7 and ISO class 5) and adjacent High Pressure Rinsing (HPR) room at ISO class 5.
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.  
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. The SEHT facility in building 198 has already been used for the ISEULT project to validate experimentally the technological concepts used (1.
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.


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