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: 2155584
CERN’s MQXFS magnet summary Coil Conductor Cu/SC RRR 293/20 K Short sample limit 1.9 K (kA) Pre-stress @ 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
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 (17.1-17.7) 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
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)
Contents Training memory Thermal cycle effect High quench integral tests Conclusions and outlook
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
#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
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
#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
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
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
Contents Training memory Thermal cycle effect High quench integral tests Conclusions and outlook
Thermal cycle* effect: MQXFS3a-b *: S3a S3b had a thermal cycle and an increase of axial preload
Thermal cycle* effect: MQXFS3a-b, 1.9 K Coil 107, O3-O4 improves after action (200 A/s)
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)
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)
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)
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
Thermal cycle effect: MQXFS5, 1.9 K No detraining Limit not reached: cannot extract conclusions
Thermal cycle effect: MQXFS5, 4.5K Quench current limit increases ~200A Training up to quench level finished ~200 A
Thermal cycle effect: MQXFS5, 4.5K Quench current limit increases ~200A Training up to quench level finished Quench signature very similar
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
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
Thermal cycle effect: MQXFS3c, 1.9 K, 200 A/s Quench current limit decreases ~100 A Quench current plateau ~100 A
Thermal cycle effect: MQXFS3c, 1.9 K, 200 A/s Quench current limit decreases ~100 A Quench current plateau Quench signature identical
Thermal cycle effect: MQXFS3c, 4.5 K, 20 A/s Quench current limit decreases ~100 A Quench current plateau ~100 A
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
Thermal cycle effect: MQXFS4 At 1.9K: training not finished before thermal cycles
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
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
Contents Training memory Thermal cycle effect High quench integral tests Conclusions and outlook
Hotspot temperature vs QI in MQXF S3c Maximum allowed: 350 K (32-34 MA2s) Only surpassed in MQXFS3c S3a-b, S4a-b S5 S6
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
Contents Training memory Thermal cycle effect High quench integral tests Conclusions and outlook
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
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