Technical Design Report Super Fragment Separator

Engineering design of the dipole coils
DRAFT
Based on the requirements of the Super-FRS the superconducting coil is operated at a constant
magnetic field and the maximum magnetic field in the dipole magnet is about 1.6 T. The engineering
design for the dipole coil system is covered by a selection of the superconducting conductor,
the structure, the fabrication technology and the quench protection.
The shape of the coil is a trapezoidal-shaped configuration with NbTi monolithic conductor of high
Cu/SC ratio. The cryostat provides the necessary vacuum and cryogenic environment for operation
of the Super-FRS dipole coils. The coil is surrounded by liquid helium in a coil case, and a thermal
radiation shield is designed and set in the cryostat. The dipole coil with case and thermal shield are
suspended by the supports.
A) Conductor
The main parameters of the conductor and the coil for the dipole magnet are listed in Table 2.4.10.
Figure 2.4.31 shows the cross section of the conductor.
Table 2.4.10: Parameters for the SC coil of the dipole magnet.
Dimension
Superconducting Strands NbTi
Dimension of Conductor 1.17 × 1.93 mm
Dimension of Conductor include insulation 1.43 × 2.24 mm
Filament diameter 50-105 µm
Number of the filaments in core wire 55
Twist pitch on filaments 13 mm
Diameter of the core wire 0.0247/0.63 Inch/mm
Ratio of Cu and no Cu in core wire 1.3
Ratio of Cu and no Cu in conductor 14
Operating temperature Top 4.2 K
n-values 84 ± 9
RRR of Cu in strand 107 ± 11
Thickness of the original insulation ∼ 0.31 × 0.26 mm
Critical current Ic1 560 @4.2 K & 4 T
Critical current Ic2 774 @4.2 K & 2 T
Critical current Ic3 (Calculated) 813 @4.2 K & 1.6 T
Operating current Iop 246 A
Density of the conductor (Iop/(1.17× 1.93)) 109 A/mm 2
Operating fraction i=Iop/Ic3
0.3
Critical temperature Tcs 7 K
Temperature margin Tcs - Top 2.8 K
34