Development of 12 T-10 Al-stabilized Nb3Sn conductor for TMC-II

The Al-stabilized Nb
3
Sn strand has been successfully fabricated and J
c
value of 400 A/mm
²
at 12 T is obtained on condition that Nb
3
Sn is reacted at 625°C for 200 hr. Overall residual resistivity of this strand is lowered to 77 % of that of the Cu-stabilized Nb
3
Sn strand (TMC-I)
^1,2
at 12 T by Al-stabilizer. The 12 T-10 kA cable-in-conduit conductor, fabricated by this strands, is charged up to 20 kA at 8.7 T without appearance of normal zone. From these experimental results, this conductor satisfies almost the specification of the present target conductor (TMC-II)
³
.