nb 3 sn development at cea/saclay j.m. rifflet
DESCRIPTION
Nb 3 Sn development at CEA/Saclay J.M. Rifflet. On behalf of: Maria Durante, Michel Segreti, Alain Przybylski and all other people who have participated to this project. Objectives of the Nb 3 Sn Quadrupole project Components and fabrication process Coils Fabrication - PowerPoint PPT PresentationTRANSCRIPT
Nb3Sn
development at CEA/SaclayJ.M. Rifflet
On behalf of:Maria Durante, Michel Segreti, Alain Przybylski and all other people who have participated to this project
J. M. Rifflet WAMSDO 19-23 May 2008
Outline
Objectives of the Nb3Sn Quadrupole project
Components and fabrication process
Coils Fabrication
Coil assembly and collaring
Warm magnetic measurement of collared coils
Current and future activities
Conclusions and perspectives
J. M. Rifflet WAMSDO 19-23 May 2008
Objectives
Learn Nb3Sn technology, using process that can be transferred to industry.
Build a quadrupole magnet based on NbTi arc quadrupoles design in order to reuse, when possible, existing components or tooling
Gradient 211 T/m
Nominal currenty
11870 A
Bmax 8.3 T
Straight part length
1 m
Section of the cold mass Wind, React and Impregnate
J. M. Rifflet WAMSDO 19-23 May 2008
Coil components 1/2
The conductor was developed in the framework of a collaboration with ALSTOM/MSA.
36 strands cable, with a 125 µm thick stainless steel strip
Cable width: 15.1 mmMean thickness: 1.48 mmKeystone angle : 0.9°
Ø strand : 0.825 mm
19 sub elements3762 filamentsanti diffusion barrier in NbTa
Jc (4.2K, 7T ) : 1850 A/mm2Ø filaments : 19 µm (effective)
J. M. Rifflet WAMSDO 19-23 May 2008
Coil components 2/2
Coil components must resist to heat treatment
Conductor insulation : S2 glass cloth (+ vacuum epoxy resin impregnation after heat treatment
End spacers : and angular wedges : CuAl9
End spacers insulation ; inter turn insulation in ends and inter layer insulation : mica foils; 0.1 mm thick
J. M. Rifflet WAMSDO 19-23 May 2008
Winding
Both layers are wound on top of each other, without junction
J. M. Rifflet WAMSDO 19-23 May 2008
Heat treatment
radially and azimuthally blocked.
Axially free
660°C plateau - 10 daysHeat treatment = 20 daysoperation : 4 weeks
J. M. Rifflet WAMSDO 19-23 May 2008
Nb3Sn/NbTi junctions
Each Nb3Sn end is soldered to NbTi . Inter coil connexions are standard NbTi connexions
1.5 week
J. M. Rifflet WAMSDO 19-23 May 2008
Instrumentation
Each coil is equipped with 13 potential wires
2
3
1
4
0
10
8
7
5
6
9
0.5 week
J. M. Rifflet WAMSDO 19-23 May 2008
Vacuum Impregnation
Epoxy resin : Araldite CY192-1 + HY918
2 weeks, including coil cleaning
J. M. Rifflet WAMSDO 19-23 May 2008
Coil Tests
Electrical and mechanical tests by ACCEL, Germany
J. M. Rifflet WAMSDO 19-23 May 2008
Coils fabrication
2 coils have been wound to check tooling and process
The 2 coils have been used for 3 collaring tests (with capacitive sensors and strain gauges
6 real coils (with checked conductor) have finally been wound
Critical points :
Metallic end spacers
winding : 2 coils with shorts
Heat treatment : how to control the mould closing; twist of the coils after unmolding , coil elongation (2 to 4 mm)
junctions : reduce space; brittle conductors
Impregnation : leaks; control of resin curing
J. M. Rifflet WAMSDO 19-23 May 2008
Coils with short between turns
2 Coils shows short between turn (jump from first to 2nd layer)
POLE 3 - MESURE 8
y = 0.00159x + 31.11597
R2 = 0.99803
y = 0.000497x + 31.103356
R2 = 0.990526
y = 0.00050x + 30.05911
R2 = 0.99781
y = 0.00160x + 30.07720
R2 = 0.99955
31
31.05
31.1
31.15
31.2
31.25
31.3
31.35
31.4
-130
-120
-110
-100 -9
0
-80
-70
-60
-50
-40
-30
-20
-10 0 10 20 30 40 50 60 70 80 90 100
110
120
130
Distance de l'extrémité de la tête (mm)
R in
tégr
ée (m
Ohm
)
29.8
29.85
29.9
29.95
30
30.05
30.1
30.15
TOUR 1
AUTOUR DU POINT 19
TOUR 2
AUTOUR DU POINT 17
J. M. Rifflet WAMSDO 19-23 May 2008
Coils with short between turns
J. M. Rifflet WAMSDO 19-23 May 2008
Coil assembly
Same principle as for LHC main quadrupoles
The magnet is equipped with 8 double capacitive sensors and 12 strain gauges
J. M. Rifflet WAMSDO 19-23 May 2008
Coil assembly
J. M. Rifflet WAMSDO 19-23 May 2008
Coil assembly
J. M. Rifflet WAMSDO 19-23 May 2008
Coil assembly
96
89
110,7
67,6
58
111,5
64
6
77
7,2
0
20
40
60
80
100
120
0 5 10 15 20 25 30 35
Step
Str
ess
(M
Pa
)
Massage 2
Keying 50%Keying 100%
Massage 1
Stress during collaring
J. M. Rifflet WAMSDO 19-23 May 2008
Warm magnetic measurement
Before inter coils connexions
-40.
-20.
0.
20.
40.
60.
80.
Position 1 Position 2 Position 3 Position 4 Position 5
Mu
ltip
ôle
s (
un
ités) b3!
a3!
b6*!
a6!
b4
a4
b5*!
a5!
J. M. Rifflet WAMSDO 19-23 May 2008
Magnet essembly
Inter coils connexions
Instrumentation wires routing
J. M. Rifflet WAMSDO 19-23 May 2008
Cold mass assembly
The cold mass assembly will take place in june 2008
3D mock-up of the cold mass(A. Acker)
J. M. Rifflet WAMSDO 19-23 May 2008
Cold tests
Cold tests will occur in SCHEMa test facility at Saclay, starting in summer 2008
Horizontal test facility SCHEMa(B. Hervieu)
J. M. Rifflet WAMSDO 19-23 May 2008
Conclusions
The Saclay’s Nb3Sn quadrupole magnet fabrication will be finished within a few weeks.
A lot of Nb3Sn specificities have been encountered.
In particular, we have learned how to repair such coils
But :
– The validity of the repair and of all the fabrication process will be proven only during cold tests (summer 2008)
– There is still work to perform in order to achieve the objective of “industrial process”
– Further development will take place (see High field magnet program in Europe – Gijs de Rijk)