The document discusses the production of a superconducting conductor called the Nb-Ti/Cu Rutherford Cable On Conduit Conductor (RCOCC) for use in a 43 Tesla hybrid magnet. The RCOCC consists of a 19 strand flat cable soft-soldered onto a hollow copper-silver stabilizer. Key parameters of the RCOCC are described. The production line for assembling the RCOCC in-house includes unspooling the copper-silver stabilizer, assembling the cable onto the stabilizer using induction heating of solder alloy ribbons, and calibrating, dimensionally controlling, and spooling the finished RCOCC onto reels. The production line at LNCMI-G

1. G. Caplanne, P. Hanoux, R. Pfister, M. Pissard, P. Pugnat, and L. Ronayette (CNRS-LNCMI Grenoble)
A. Ravni, L. Ravni, and Th. Tremblay (Ravni Technologies)
Towards In-house Industrial Assembly of the Superconducting Conductor
for the 43 T Hybrid Magnet
Fig. 1. Production line of the Cu/Nb-Ti Rutherford Cable On Conduit Conductor (RCOCC).
The Nb-Ti/Cu Rutherford Cable On Conduit Conductor
(RCOCC) is composed by a 19 strand flat cable soft-
soldered on a hollow Cu-Ag stabilizer. This will allow
obtaining a superconducting coil internally cooled down
to 1.8 K by a static bath of superfluid helium at
atmospheric pressure. RCOCC parameters are listed in
Table 1.
Parameters Values
Width 12.96 ± 0.05
Height 18 ± 0.05 mm
Copper cross-section of the stabilizer ≥ 157.5 mm2
Cooling channel diameter 6 mm
Elastic limit (0.2%, 300 K) after soldering > 230 MPa
RRR of the stabilizer after soldering 50 ± 10
Twist pitch of the Rutherford cable (Lp)  140 ± 5 mm
Strand diameter 1.62 ± 0.02
Strand Cu/Nb-Ti ratio 1.30 ± 0.05
Filament diameter / twist pitch 15 m / 15 mm
Nominal / ultimate current (8.5 / 9 T) 7100 / 7500 A
Ic* of the RCOCC at T = 1.9 K & B = 10 T > 20 100 A
Unit length 280 m
* Margin on the peak field load line of 21 % as well as a temperature
margin of 2.2 K at nominal current and peak field equal to 9.35 T.
Table 1. Main Parameters of the RCOCC.
The two main requirements of the RCOCC are
mechanical and electrical: i) State-of-the-art soft-
soldering of the Rutherford cable on the Cu-Ag hollow
stabilizer; ii) Low inter-strand coupling currents to
avoid quenching of the magnet during a trip of the
power converter of the resistive insert coils. This can be
achieved by a strict control of the amount of solder
alloy used in addition to the stainless steel core inserted
within the Rutherford cable. For the RCOCC assembly,
the industrial process will be based on induction heating
of solder alloy ribbons of 0.15 mm thick instead of
using a melted solder bath. Mechanical properties of
soft-soldered RCOCC obtained from various ribbons of
solder alloy have been thoroughly tested and analyzed
leading to the final choice of Sn61.5Pb37Sb1.5 alloy with a
liquidus temperature of 190°C.
The RCOCC production line shown in Fig.1 can be
split in 5 major parts. The first one allows the
unspooling of the Cu-Ag stabilizer. The second one
contains 2 caterpillars, the straightening rollers, the
fluxing system before ending with the RCOOC
assembly head. The third part is made of the induction
heating head, the crimping one and the air cooling
system. The fifth part contains a water cooling system,
the ultrasonic control system of the soft soldering,
followed by calibration and dimensional control heads.
The last part is composed by the single pancake
RCOOC delivery spool with internal diameter equal to
2 m, i.e. larger than the maximum diameter of the final
coil winding, as well as the reel for the protection sheet
to be inserted between turns. The delivery date for the
production line at LNCMI-Grenoble will be at the latest
beginning of 2016 and the duration of the RCOCC
production is estimated not exceeding 4 months.