Sandrine Le Naour - MSC-CMI

MSC-CMI meeting, 16/12/2013
Sandrine Le Naour
Bat 163 : Superconductivity Lab
Pumps and
compressor
Control
room
Cold
Box
Workshop
7 test stations for strand characterization
1 test station for cable characterization : Fresca




Helium liquifier: (cold box + compressor) rate ~130l/h
Station of demineralized water : 20m3/h
6 pumps for characterisation at 1.9K
2 furnaces for Nb3Sn reaction (Vamas)
Bat 163 : Superconductivity Lab
Workshop
Pumps and
compressor
Control
room
Name
Ic
Ic
Ic
Ic
Sample PS
1kA
1kA
4kA
4kA
Magnet
15T
11T
13T
15T
M(B)
VSM
RRR
-
-
few A
1.5T
11T
+0.1T@10Hz
bore of magnet 70mm




100 mm
100mm
70mm 100 mm
88 mm
4 test stations for Ic on strands
2 test stations for Mg on strands
1 test station for RRR
Fresca
FRESCA
32kA
10T (16kA)
Cold
Box
Fresca
Fresca
"Quick
Quick
connect" connect
F
2 cryostats :
F
Rotating
system
Current leads of
Current leads
the
magnet
(16kA)
magnet
16 kA
Rotating system
Current leads
sample 32 kA leads of the sample (32kA)
Current
Inner cryostat2
Inner
cryostat
Liquid-gas heat heat exchanger
Liquid-gas
exchanger
Outer cryostat :

NbTi dipole magnet of ~10T
if operated at 1.8K.

Uniform field on 600mm
Lambda plate
Lambda
sample holder plate of the sample holder
Lambda
Lambda plate plate of the inner cryostat
4.2 K
1.9 K
inner cryostat
Liquid-liquid
Liquid-liquid
heat exchanger
heat exchanger
4.2 K
Lambda
outer cryostat plate of the outer cryostat
Lambda plate
Sample
holder
Sample
holder
Background
Dipole
magnet
Magnet
Inner cryostat :

Φint : 72mm, ~2m long

Sample powered up to
32kA,

The sample can be cooled
down at 4.3K or 1.9K
Outer
cryostat
Outer
1.9 K
cryostat
Sample preparation to be seen
in the preparation zone…
Critical current test stations
First dedicated to LHC strand qualification for NbTi
strands (55000 samples measured over 5 years with Mg and RRR),
now most of the measurements
are done for Nb3Sn conductor.
Critical current density values
For a critical current, different parameters
must be given such as :
 Temperature
 Magnetic field (intensity, direction)
 Criteria (electric field or resistivity)
 Strain
 Specify if Ic over matrix or not
Electrical field [µV/cm]
1.2
1
n=10
0.8
n=25
0.6
n=60
Resistivity
0.4
Electrical Field
0.2
0
0.4
0.6
0.8
1
I/Ic
1.2
1.4
Nb3Sn wires: Different process
Graph from Luca’s presentation
at EUCAS 13
Magnetization test station
VSM (Vibrating Sample Magnetometer)
With a VTI (variable temperature insert) : 1.9K -> 300K
Magnetic field : 10.5 T
Sample vibration : 20Hz
Magnetization
Superconductor : diamagnetic propriety
40
α Jc (critical current density)
α d (filament diameter)
Magnetization [mT]
30
-0.5
-0.3
20
10
0
-0.1
-10
-20
-30
-40
0.1
0.3
0.5
0.7
0.9
Magnetic field [T]
1.1
RRR = ρ300 K/ρ>Tc
Super conductor Tyranno
Critical current measurement comparison