1. Long term behavior and high-QI test in the MQXFS program
Franco Mangiarotti, Hugo Bajas
Gerard Willering, Michał Duda, Marta Bajko, Vincent Desbiolles, Jerome Feuvrier
Thanks to support throughout the section, group and project.
2019/05/23, WP3 meeting.
EDMS:

2. CERN’s MQXFS magnet summary
Coil
Conductor
Cu/SC
RRR
293/20 K
Short sample limit 1.9 K (kA)
1.9 K Az. (MPa) / Ax. (kN)
MQXFS3a-b 7
RRP 108/127
1.2
185
21.60
A: 110 / 0.7
B: 110 / 1.15
105
RRP 132/169
143
21.55
106
159
107
144
21.33
MQXFS5
203
PIT 192 80
20.87
120 / 1.2
204 88
20.86
205
21.00
206 90
20.54
MQXFS3c 8
172
140 / 1.05
MQXFS4a-b
108
170
22.20
109
160
22.60
110
165
22.00
111
MQXFS6a
208
PIT 192 BB 74
20.93
209 72
20.90
210
20.51
212 97
20.64
Chronological order
Final design

3. CERN’s MQXFS tests summary
Magnet
Test Station
# CDs
Reached Ultimate
(17.9 kA)
Reached limit 1.9 K
4.5 K verif
Ramp rate studies
VI meas.
Max QI
High current cycles§
QH firings
MQXFS3a-b
HFM 2*
N (61 Q)
Y ( ) Y N
30.4 (~280 K)
101
112
MQXFS5 D 2
Y (28 Q)
N (18.5 kA)
26.6 (~230 K) 85 97
MQXFS3c
Y (16 Q)
Y (18.1 kA)
40.3 (>400 K)
113 95
MQXFS4a-b
HFM/D 3
Y (5 Q)
30.6 (~280 K) 40 71
MQXFS6a 1
N (23 Q)
Y (16.4 kA)
18.5 (~120 K) 28 26
Chronological order
Ultimate current: 17.9 kA
Maximum target current: 18.5 kA
Nominal maximum allowed hotspot temperature: 350 K (~34 MA2s)
§: only current cycles above 80% of nominal current (13.2 kA)
*: MQXFS3a  3b had a change of pre-stress

4. One* word about MQXFS6 We have done many measurements of MQXFS6
Magnet training
We have done many measurements of MQXFS6
But we have done few current cycles, no thermal cycle and no high QI tests, so these results are not being used for the present analysis.
More info about MQXFS6 tests here and here.
Ramp rate dependency at different temperatures
Voltage measured during 1 A/s ramp (starts at 2600 s)

5. Contents
Training memory
Thermal cycle effect
High quench integral tests
Conclusions and outlook

6. Training memory: S3a  S3b
Action
Coil
Magnet
Imax [kA]
#q after action until Imax
Increase axial pre-stress 7
S3a  S3b
17.1
(200 A/s)
0 (4 at 20 A/s)
105
106
107
2x Thermal cycle
203 S5
18.1
204
1 (total)
205
206
Increase az.
pre-stress,
Coil change
S3b  S3c
17.7 2
3 (HF inst. at 20 A/s)
Thermal cycle 8
S3c
N/A (0 to plateau)
N/A (1 to plateau)
108
S4a
S4a  S4b
109
110
111
Ultimate current = 17.9 kA

7. #q after action until Imax
Training memory: S5
Action
Coil
Magnet
Imax [kA]
#q after action until Imax
Increase axial pre-stress 7
S3a  S3b
17.1
(200 A/s)
0 (4 at 20 A/s)
105
106
107
2x Thermal cycle
203 S5
18.1
204
1 (total)
205
206
Increase az.
pre-stress,
Coil change
S3b  S3c
17.7 2
3 (HF inst. at 20 A/s)
Thermal cycle 8
S3c
N/A (0 to plateau)
N/A (1 to plateau)
108
S4a
S4a  S4b
109
110
111
Ultimate current = 17.9 kA

8. Training memory: S3b  S3c
Action
Coil
Magnet
Imax [kA]
#q after action until Imax
Increase axial pre-stress 7
S3a  S3b
17.1
(200 A/s)
0 (4 at 20 A/s)
105
106
107
2x Thermal cycle
203 S5
18.1
204
1 (total)
205
206
Increase az.
pre-stress,
Coil change
S3b  S3c
17.7 2
3 (SF inst. at 20 A/s)
Thermal cycle 8
S3c
N/A (0 to plateau)
N/A (1 to plateau)
108
S4a
S4a  S4b
109
110
111
Ultimate current = 17.9 kA

9. #q after action until Imax
Training memory: S3c
Action
Coil
Magnet
Imax [kA]
#q after action until Imax
Increase axial pre-stress 7
S3a  S3b
17.1
(200 A/s)
0 (4 at 20 A/s)
105
106
107
2x Thermal cycle
203 S5
18.1
204
1 (total)
205
206
Increase az.
pre-stress,
Coil change
S3b  S3c
17.7 2
3 (HF inst. at 20 A/s)
Thermal cycle 8
S3c
N/A (0 to plateau)
N/A (1 to plateau)
108
S4a
S4a  S4b
109
110
111
Ultimate current = 17.9 kA

10. Training memory: S4a, S4a  S4b
Action
Coil
Magnet
Imax [kA]
#q after action until Imax
Increase axial pre-stress 7
S3a  S3b
17.1
(200 A/s)
0 (4 at 20 A/s)
105
106
107
2x Thermal cycle
203 S5
18.1
204
1 (total)
205
206
Increase az.
pre-stress,
Coil change
S3b  S3c
17.7 2
3 (HF inst. at 20 A/s)
Thermal cycle 8
S3c
N/A (0 to plateau)
N/A (1 to plateau)
108
S4a
S4a  S4b
109
110
111
Ultimate current = 17.9 kA

11. Training memory summary
Action
Coil
Magnet
Imax [kA]
#q after action until Imax
Increase axial pre-stress 7
S3a  S3b
17.1
(200 A/s)
0 (4 at 20 A/s)
105
106
107
2x Thermal cycle
203 S5
18.1
204
1 (total)
205
206
Increase az.
pre-stress,
Coil change
S3b  S3c
17.7 2
3 (HF inst. at 20 A/s)
Thermal cycle 8
S3c
N/A (0 to plateau)
N/A (1 to plateau)
108
S4a
S4a  S4b
109
110
111
Very good / perfect memory (except when mechanically damaged)
Ultimate current = 17.9 kA

12. Contents
Training memory
Thermal cycle effect
High quench integral tests
Conclusions and outlook

13. Thermal cycle* effect: MQXFS3a-b
*: S3a  S3b had a thermal cycle and an increase of axial preload

14. Thermal cycle* effect: MQXFS3a-b, 1.9 K
Coil 107, O3-O4 improves after action (200 A/s)

15. Thermal cycle* effect: MQXFS3a-b, 1.9 K
Coil 107, O3-O4 improves after action (200 A/s)
Coil 105, O2-O3 improves after action (300 A/s)

16. Thermal cycle* effect: MQXFS3a-b, 1.9 K
Coil 107, O3-O4 improves after action (200 A/s)
Coil 105, O2-O3 improves after action (300 A/s)
Coil 7, I3-I4 degrades after action and after current cycles (20 A/s)

17. Thermal cycle* effect: MQXFS3a-b, 1.9 K
Coil 107, O3-O4 improves after action (200 A/s)
Coil 105, O2-O3 improves after action (300 A/s)
Coil 7, I3-I4 degrades after action and after current cycles (20 A/s)

18. Thermal cycle* effect: MQXFS3a-b, 4.5 K
Both in coil 105 but different location:
Q.34: inner layer pole turn
Q.61 & 61: outer layer pole turn
Increase of quench current (~ 300 A)
Cannot discard training

19. Thermal cycle effect: MQXFS5, 1.9 K
No detraining
Limit not reached: cannot extract conclusions

20. Thermal cycle effect: MQXFS5, 4.5K
Quench current limit increases ~200A
Training up to quench level finished
~200 A

21. Thermal cycle effect: MQXFS5, 4.5K
Quench current limit increases ~200A
Training up to quench level finished
Quench signature very similar

22. Thermal cycle effect: MQXFS5, 4.5K
Quench current limit increases ~200A
Training up to quench level finished
Quench signature very similar
No precursor
Resistive voltage buildup slower after thermal cycle (larger margin to Ic?)
Before TC
After TC

23. Thermal cycle effect: MQXFS3c
This magnet is limited at 1.9K, 20 A/s by self field instability in coil 106
Coil 107 doesn’t show this instability
Quenches marked with start in 107 O2-O3

24. Thermal cycle effect: MQXFS3c, 1.9 K, 200 A/s
Quench current limit decreases ~100 A
Quench current plateau
~100 A

25. Thermal cycle effect: MQXFS3c, 1.9 K, 200 A/s
Quench current limit decreases ~100 A
Quench current plateau
Quench signature identical

26. Thermal cycle effect: MQXFS3c, 4.5 K, 20 A/s
Quench current limit decreases ~100 A
Quench current plateau
~100 A

27. Thermal cycle effect: MQXFS3c, 4.5 K, 20 A/s
Quench current limit decreases ~100 A
Training up to quench level finished
Quench signature identical

28. Thermal cycle effect: MQXFS4
At 1.9K: training not finished before thermal cycles

29. Thermal cycle effect: MQXFS4
At 1.9K: training not finished before thermal cycles
Quench current increases at 400 A/s (only 1 quench each TC)
~300 A

30. Summary of thermal cycle effect
S3a-b: locations in coil 105 and 107 improve, one location in coil 7 degrades
Not a “clean” thermal cycle
S5: ~200 A increase of coil 206 limit
S3c: ~100 A reduction of coil 107 limit
S4: quench current improvement at 1.9 K, 400 A/s
Limited statistics (1 quench per TC)
S6: no thermal cycle

31. Contents
Training memory
Thermal cycle effect
High quench integral tests
Conclusions and outlook

32. Hotspot temperature vs QI in MQXF
S3c
Maximum allowed:
350 K (32-34 MA2s)
Only surpassed in MQXFS3c
S3a-b,
S4a-b S5 S6

33. High Quench Integral: MQXFS3c coil 106
Procedure:
Baseline 4.5 K quench (107 O2-O3)
High QI quench at 1.9 K, 20 A/s
Verification quench at 1.9 K, 20 A/s
Verification quench at 4.5 K (107 O2-O3)
Conclusions:
At 1.9 K, 20 A/s: self field instability dominates
At 4.5 K: same limit in coil 107
In coil 106, no degradation up to ~90% of its short sample limit at 4.5 K

34. Contents
Training memory
Thermal cycle effect
High quench integral tests
Conclusions and outlook

35. Retraining after TC: one quench/coil Quench limit same or improved…
Conclusions
Magnet
Retraining after TC: one quench/coil
Quench limit same or improved…
after powering
after th. cycle
After high QI
S3a-b
Yes No
Probably yes
N/A S5
S3c
Yes*
4a-b 6a
Chronological order
* S3b  S3c had up to 3 quenches per coil to the same current level after thermal cycle + change of coil + azimuthal load increase. The thermal cycle in S3c had up to 1 quench per coil to the new plateau

36. Outlook: test of MQXFS4c
We can compare:
4.5 K, 20 A/s
1.9 K, 20 and 200 A/s (no quench)
1.9 K, 400 A/s
We can add:
VI measurements
4.5 K at higher ramp rates
AC losses
Other?
C109_I2-I3
C111_I2-I3
C111_I3-I4
C109_O1-O2
C109_O2-O2
C109_I2-I3
C110_I3-I2
“-” symbol represents no-quench