1. The CMS magnet superconducting coil
The CMS magnet project
The CMS magnet was financed by an international collaboration of 23 countries and CERN. The magnet coil design and construction follow up was coordinated by teams from CEA (France), CERN, ETHZ (Switzerland), FNAL (USA), INFN (Italy).
Coil sample longitudinal
cross section
CMS Magnet main parameters
Central field of 3.8 Tesla in operation (designed for 4 Tesla)
Stored energy 2.7 GJ
Superconducting solenoid Ø 6 m, 12.5 m long
Winding with 4 layers of conductor and an external mandrel
Coil inductance : 14 Henry
Cold mass weight: 225 tons
Axial forces on the coil mid plane at 4 Tesla: 147 MN
Magnetic radial pressure on the coil at 4 Tesla: 64 bars
CERN / CMS - Feb. 2005
CMS Superconductor key parameters
Magnet dc operating current: 18.2 kA
Critical current: 60 kA at 4.2 K, 5 T
Operating temperature: 4.5 K, cooling with LHe thermo-syphon
CMS magnetic flux density vector sum
in the longitudinal cross section (in Tesla)
Conductor Cross section
32-strand NbTi superconducting cable
High Purity Aluminum 5N8 stabilizer
Aluminum alloy reinforcement
1- Vertical assembly of the CMS coil modules in SX5
Electron Beam welding
CERN / CMS - Aug. 2005
CERN / CMS - Jan. 2006
CERN / CMS - Feb. 2007
5- Lowering the central barrel with the coil to the UXC5: 2’000 tons in one go at a depth of 100m.
2- CMS coil swiveling in the SX5 surface hall
4- CMS magnet ready for testing in the SX5
CERN / CMS - Sept. 2005
CERN / CMS - Nov. 2007
6- Central barrel and cryostat covered by detector cables
and cooling circuits in the final position in UXC5
3- Coil introduction into the cryostat on central barrel YB/0 in SX5
Poster author: Benoit CURE, CERN-PH, CMS Collaboration.