1. Block design status EuroCirCol
Clément Lorin, Maria Durante
16 may 2017
Acknowledgements:

2. Critical surface Nb3Sn Jc (1.9 K, 16 T) = 2245 A/mm² no cabling degr.
C0 = AT/mm²
where t = T/Tc0 and b = B/Bc2(t) with B the magnetic flux density on the conductors. Tc0 = 16 K, Bc20 = 29.38 T, α = 0.96, are fitting parameters computed from the analysis of measurements on the conductor.
Similarly:
Jc (1.9 K, 16 T) = 2312 A/mm²
3% cabling degr.
C0 = AT/mm²

3. Design evolution bore tip th. decrease
Quantity
ASC2016
v20ar
v1ari204
Unit
strand diameter
1.1 – 0.7
1.155 – 0.705
1.15 – 0.70 mm
nb of strands
24 – 39
21 – 35
20 – 34
N/A
width
14.25
13.05
12.6
average thickness
2.0 – 1.25
2.1 – 1.25
Cu/nonCu
0.8 – 1.6
0.8– 2.3
0.8– 2.0
Inom
10930
10990
10465 A
Bpeak
16.81
16.74
16.72 T
LL margin (1.9 K)
13.95
14.01
13.94 %
Inductance diff. (2 ap)
48.06
39.80
44.2
mH/m
Stored energy (2 ap)
3016
2518
2542
kJ/m
Nb of turns
114 =
104 =
108 = -
Fx & Fy (per ½-coil)
8473 & -3572
8042 & -3347
8042 & -3329
kN/m
Hotspot
348
349
351 K
Bore thickness
6.3
1.75
1.6
Midplane shim
1.45
2.25
LdxI (1 aperture)
263
218
232
HA/m
I/Ic HF-LF
0.47 – 0.61
Conductor area (2 ap)
151.9
133.7
130.3
cm²
4578 x 14.3 x 8.7 weight
8652
7614
7420
tons
= v20ar
v1ari204
bore tip th. decrease
interbeam decrease (250mm -> 204 mm)
insulation = 0.15 mm

4. Harmonic contents v1ari204: higher cross-talking (b2 = 24 units)
at nominal 16 T:
1 T
3.3 T
16 T

5. Fringe field
R = 1 meter -> Bnorm ~ 3 mT
R = 1 m 0°
90°

6. Emag 3D Opera model: Bpss-Bpends = 0.4 T
Lyoke = Lcoil = 1780 mm
Lpads = 1100 mm
Lmag = 1498 mm
141 mm
340 mm
Harmonics from 560 mm to 960 mm (orange box)
b3 can be easily tuned
Bpss-Bpends = 0.4 T

7. Emag 3D - Optics
Question asked to beam guys (WP2, A. Chance, B. Dalena):
No straight section length effect
What we usually do:
Optimization depends on the SS length
14 m with b3 = 6 units
2x0.15 m with b3 = -300 units
To get more compact ends for block design
Is that feasible?

8. Need validation/correction
Graded: how?
Need validation/correction
by Etienne et Susana
Two options:
External connexions vs Internal connexions
Courtesy from Etienne Rochepault
CERN
Development program CERN, CEA, PSI,…?
Pros&Cons:
-Coil assembly: cable to take care
-End parts: cable path outwards
-Additional connexion box
-Shorter ends
-Connexion length
-Splice in low field area
Pros&Cons:
-Length of the splice (not long enough < Tp)
-Gap between LF&HF: longer ends
-Splice in high field area
-Coil assembly easier
-End parts simpler

10. Mechanics v1ari204 63 mm thick shell 700 µm ← 50 µm ↓
1.6 mm thick bore tip
Ryoke = 273 mm
Contacts/symmetry:
sliding; 0.2 friction
glued: coils with pole vertically
and with shoes
rail is a block for rigidity

11. Coil stress v1ari204 Contact at 105% σ von Mises σhorizontal Keys in
106 MPa
-117 MPa
190 MPa
-203 MPa
185 MPa
-186 MPa
Contact at 105%
16.8 T central field
105 % nominal
-19 MPa
+145 MPa
16.0 T central field
100 % nominal
+11 MPa
+98 MPa

12. Coil displacement Before key insertion to nominal powering 16 T
x horizontal disp.
y vertical disp. 1 2 3 4 5 6 1 2 3 4 5 6
u1x_nominal = µm
u2x_nominal = µm
u3x_nominal = µm
u4x_nominal = µm
u5x_nominal = -440 µm
u6x_nominal = -368 µm
u1y_nominal = µm
u2y_nominal = -146 µm
u3y_nominal = -171 µm
u4y_nominal = -255 µm
u5y_nominal = -192 µm
u6y_nominal = µm
compaction
~ 1% of cable width

13. Aluminum shell Cold – 4.2 K 16.8 T (105% nominal) Key σ theta Rp0.2 RT
480 MPa
690 MPa
Cold – 4.2 K
16.8 T (105% nominal)
Key
σ theta

14. Iron yoke Cold – 4.2 K 16.8 T (105% nominal) Key σ von Mises
Rp0.2 RT
cold/tension
Magnetil
180 MPa
230 MPa
723 MPa/200 MPa
723 MPa/380 MPa
Cold – 4.2 K
16.8 T (105% nominal)
Key
σ von Mises
σI – tension max

15. Iron pad1 Cold – 4.2 K 16.8 T (105% nominal) Key σ von Mises
Rp0.2 RT
cold/tension
Magnetil
180 MPa
230 MPa
723 MPa/200 MPa
723 MPa/380 MPa
Cold – 4.2 K
16.8 T (105% nominal)
Key
σ von Mises
σI – tension max

16. Iron pad2 Cold – 4.2 K 16.8 T (105% nominal) Key σ von Mises
Rp0.2 RT
cold/tension
Magnetil
180 MPa
230 MPa
723 MPa/200 MPa
723 MPa/380 MPa
Cold – 4.2 K
16.8 T (105% nominal)
Key
σ von Mises
σI – tension max

17. Titanium pole Cold – 4.2 K 16.8 T (105% nominal) Key σ von Mises
Rp0.2 RT
cold/tension
Ti-6Al-4V
827 MPa
1624 MPa
Cold – 4.2 K
16.8 T (105% nominal)
Key
σ von Mises
489 MPa
891 MPa
1140 MPa

18. Conclusion Bore tip to be modified Vertical pad to be modified
1.75 mm / ground ins. taken into account
Vertical pad to be modified
Roundish angle -> Emag impact
Double aperture
Split vertical key to improve coil-pole contact and reduce peak stress (230 MPa*)
Start working on 204 mm interbeam
Shall we stop working with 1.15 mm strand? Demonstrator strands?
*260 MPa: H. Felice et al. Performance of Nb3Sn quad under high stress

20. Key position
18 mm
20 mm
27 mm
25 mm
Single aperture:

21. extra Coil stress v1ari204 Contact at 100% σ von Mises σhorizontal
Keys in
1.8 K
16.8 T
σ von Mises
σhorizontal
91 MPa
-101 MPa
175 MPa
-187 MPa
159 MPa
-175 MPa
Contact at 100%
16.0 T central field
100 % nominal
-3 MPa
131 MPa
About 10 to 15 MPa less than a contact at 105%
σeq (100%,4.2K) = 175 MPa
σx (105%, 4.2K) = -203 MPa