1. 11 T dipole coil features and dimensions
Christian Löffler and Emelie Nilsson
19/10/2016
11 T dipole coil features and dimensions

2. Outline Main parameters of the coil
Nominal vs measurements
Coil cross section – nominal vs inspected coil segment
Cable insulation
Include estimates on cable degradation

3. Tolerances on the coil Angle Loading Plate ±0.2°, nominal 18.387°
Outer Radius ±0.15mm, nominal 60.8mm
Azimuthal(AZ) Branch Length ±0.15mm, nominal 0.15mm
AZ-Length is a function of the arc length and the outer diameter
0.1mm deviation is corresponding to a change of 15MPa in Coil Block 4, in AZ-Stress. This is confirmed by FEA, Mechanical Measurements and FUJI-paper analysis.
Internal Reference: FEA version: in1-cableV3_3; FUJI-Paper measurement: EDMS

4. Results from previous coils
For analysis coil separated in Ends, Center and Left and Right-Branch -> 4 values per coil
Features analyzed
LP-Angle
Outer Radius
Azimuthal Excess
End 0-500mm
Center mm
End mm

5. Results from previous coils
Tolerances ± 0.2°
End
Center
EDMS
Left-Branch
Right-Branch
Radial pressure distribution during pre-collaring of SP105, average over 10mm longitudinal. Measured with FUJI-Paper.

6. Results from previous coils
Tolerances ±0.15mm
Best-Fit of a non constrained circle on the measured point on the outer radius.

7. Results from previous coils
Branch length
0.15mm Goal
only in the very end of the straight section
Azimuthal Excess
Tolerances ±0.15mm

8. Comparison with coil segment coil #107
Nominal conductor position compared to the inspected cross section of a segment from coil #107 (photograph from MME)
Deviation of radial position of inner layer blocks
Reduced radial space between conductors near mid plane Due to over compression at some point (when closing the reaction/impregnation moulds)?

9. Image analysis on coil segment
For MQXF: E. Rochepault et al. IEEE 2016
1. Detect cable contours
2. Fit them to trapezoids

10. Summary of analysis conductor growth
Cables are curved on the middle  Fit 1/8 of the length near each end
SEGMENT FROM COIL 107
Nominal (mm)
Photograph + image analysis
Tomography + image analysis
(block 1 & 5)
Tomography + image analysis Scheuerlein
Width
14.85 (1%)
(0.1%)
(0.6%)
14.76 (0.4%)
Mid thickness
1.306 (4.5%)
1.272 (1.8%)
1.322 (5.8%)
1.296 (3.7%)
Uncertainties in measurement method and pixel sixe.

11. Cables seem to be systematically ‘bent’, in the upward direction
MICA is C-shaped with an opening on the top side (coincidence?)

12. Cable insulation Nb3Sn Cable, Mica insulation, Glass Sleeved
Insulation thickness (design values)
MICA layer
0.080 mm
Fibre braiding
0.075 mm
Total insulation thickness
0.155 mm (0.100 mm under 30 MPa compression)
Nb3Sn Cable, Mica insulation, Glass Sleeved

13. 10 stack measurements insulation thickness
Measurements show that the total insulation thickness in the range μm.
Tooling designed considering compression of the cable at 30 MPa with wall thickness of 100 μm.
Original braiding: yarn count 14/2 cm (Coil , 110).
Updated braiding: yarn count 12/2 cm.
coil
Ins 30 Mpa (μm)
105
114
106
107
108
109
110
113
111
112
115
116
117
Original braiding
105 and 110 braifing gen 1 L yarn count 14/10 mm
Updated braiding

14. Measurement of MICA thickness
10 layers of MICA piled up
Thickness per layer of MICA:
Measure 2:
MICA between bare cables in 10-stack config.

15. Modify braiding parameters
Attempt to reach design value mm
Insulation thickness S2 glass 11 TEX 636 [µm]
S2-glass Braiding parameters
# 1
11 T reference
# 2
# 3
# 4
# 5
# 5b
(with MICA)
Yarn count/2 cm 12 18
17-18
No. of brins 9 6 5 4
32*9 11 TEX

16. Results 10-stack measurements
Insulation thickness S2 glass 11 TEX 636 [µm]
Pressure [MPa] 
# 1
11T ref.
# 2
# 3
# 4
# 5
# 5b (with MICA) 5 93 66 57 70 58
100 10 89 63 54 55 20 85 59 50 52 88 30 82 48 61 84 49 83 62 51 86 60 64 87
MICA adds ~35 um (Difference #5 to #5b)
Samples to be produced and measured with MICA
Prediction of
# 4 (18 yarn counts/2 cm, 5 brins) with MICA : ~96 um
# 4 (18 yarn counts/2 cm, 6 brins) : ~105 µm
Plan to reach nominal with new braiding parameters (2nd generation short model).
Also for 1st generation long coil?

17. Heat Treatment MICA layers to avoid gluing, removed after HT
1 layer mm MP
1 layer of MICA mm on OL
1 layer of MICA mm on IL – tooling designed for 2 layers
 Coil already oversized before heat treatment?
Rmandrin = mm
Rcoil,inner = 30.0 mm
Rcoil,outer = 60.6 mm
LHCMBHST0009
Reaction tool LHCMBHST0009
At meeting: Better to use 2 layers (like in MQXF), is safer. Maybe not enough space?

18. Conclusion Short models produced: Segment of coil #107 analysed.
3/11 coils with outer radius within tolerances.
6/11 coils with loading plate angle within tolerances.
7/11 coils with azimuthal excess within tolerances. Coils are all azimuthally oversized!
Segment of coil #107 analysed.
Difficult to quantify cable dimensions.
Visible radial deviation from nominal cable positions.
To exclude effect from ‘cutting’, useful to look inside coil segment: tomographic measurements will be presented in talk later today.
Strategy to reach design values of cable insulation ( Mpa)
New braiding parameters are being explored.
To be implemented for 2nd generation 11 T coil design.
Interesting also for 1st generation long model?

19. Extra slides

20. Main parameters of the coil
Coil: 56 turns, 2 layers, 6 blocks design, no internal splice
Coil ID / OD
59.8 / 121.6 mm
Coil overall length
5559
Straight section length
5108
Turns Inner Layer (IL) / Outer Layer (OL)
22 (IL) / 34 (OL)
Impregnation System
Epoxy DGEBA (CTD 101-K)
Cable : RRP 0.7 mm dia. , 40 strands, cored, glass-mica insulated
Cable Length (IL / OL / on spool)
235 (IL) / 364 (OL) / 680 m
Cable bare width before / after reaction
14.7 / (+1%)
Cable bare mid-thickness before / after reaction
1.25 / (+4.5%)
Keystone angle before / after reaction
0.79 / 0.806
deg.
Number of strands per cable (x strand diameter)
40 (x 0.7d [mm]) -
Cable insulation wall thickness (design value)
0.1
Insulation Material
Phlogopite + Glass