US LHC Accelerator Research Program bnl fnal lbnl

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US LHC Accelerator Research Program bnl - fnal- lbnl - slac TQ Internal Review

US LHC Accelerator Research Program bnl - fnal- lbnl - slac TQ Internal Review Nov 29 – Dec 1, 2006 TQC 01 cold test and analysis G. Ambrosio Outline: • Quench performance • Magnetic measurements • Instrumentation TQ Internal Review Nov 29 – Dec 1, 2006 TQC 01 test and analysis

Test Plan TQ Internal Review Nov 29 – Dec 1, 2006 TQC 01 test

Test Plan TQ Internal Review Nov 29 – Dec 1, 2006 TQC 01 test and analysis 2

TQC 01 Test – Quench Summary At 4. 5 K, first quench was at

TQC 01 Test – Quench Summary At 4. 5 K, first quench was at 7. 7 k. A. After 11 quenches, current was still at 9 k. A, 70% of short sample At 1. 9 K, training continued, reaching 12 k. A (200 T/m), about 85% of short sample. TQ Internal Review Nov 29 – Dec 1, 2006 TQC 01 test and analysis 3

# 42 Temperature dependence Thermal cycle Training Ramp rate Quench Protection Study TQ Internal

# 42 Temperature dependence Thermal cycle Training Ramp rate Quench Protection Study TQ Internal Review Nov 29 – Dec 1, 2006 TQC 01 test and analysis 4

Quench Positions (from #1 to # 41) Cable B 2 13 B 1 10

Quench Positions (from #1 to # 41) Cable B 2 13 B 1 10 B 1 9 B 2 12 34 36 37 23 Lead End Return End Quench positions at 4. 5 K (green) and 1. 9 K (white). Figure is shown looking at the inside surface of the inner coils High ramp rate quenches not shown All quenches on the inner pole turns Quenches 33, 36 and 37 on lead end pole turn close to non-lead side Quench 34 propagated to layer-jump TQ Internal Review Nov 29 – Dec 1, 2006 TQC 01 test and analysis 5

# 42 Coil 9 OL Thermal cycle Coil 13 OL TQ Internal Review Nov

# 42 Coil 9 OL Thermal cycle Coil 13 OL TQ Internal Review Nov 29 – Dec 1, 2006 TQC 01 test and analysis 6

Temperature Dependence Note: temperature dependence studies were performed after quench #42 Coil 9 OL

Temperature Dependence Note: temperature dependence studies were performed after quench #42 Coil 9 OL Highest current at 4. 5 K before q #42 Range at 4. 5 K plateau before q #42 Coil 13 OL TQ Internal Review Nov 29 – Dec 1, 2006 TQC 01 test and analysis 7

Quench Positions (at 20 A/s from # 42 to end) All quenches in Coil

Quench Positions (at 20 A/s from # 42 to end) All quenches in Coil 9 started in segment B 3 -B 2 (outer layer body) Some of them showed small signals (~5 m. V in 10 ms) after 1 ms in adjacent segments (splice, and B 3 -B 4) Q #52 showed some development in segment B 4 -B 5 All quenches in Coil 13 started in segment B 2 -BSH 1 (mid-plane turn lead side) and propagated into the splice within 1 -10 ms TQ Internal Review Nov 29 – Dec 1, 2006 TQC 01 test and analysis 8

Ramp Rate dependence 12 I 13 Ob 12 R 10 O Ramp rate studies

Ramp Rate dependence 12 I 13 Ob 12 R 10 O Ramp rate studies at 4. 5 K performed before 1. 9 K training 13 O 12 I 13 I TQ Internal Review Nov 29 – Dec 1, 2006 12 I Maximum current at 1. 9 K (12 k. A) was reached at 100 A/s and 125 A/s TQC 01 test and analysis 9

Quench Propagation Velocities at 4. 5 K Magnet was still training Low propagation speeds

Quench Propagation Velocities at 4. 5 K Magnet was still training Low propagation speeds large Ic margin RRR Coil 1: 261 Coil 2: 242 TQ Internal Review Nov 29 – Dec 1, 2006 TQC 01 test and analysis 10

Quench Antenna data analysis Quench antenna was used to estimate the longitudinal position of

Quench Antenna data analysis Quench antenna was used to estimate the longitudinal position of quench start Two sets of coils (C 2 and C 3) cover the magnet The plot shows the starting time of signal development in voltage taps (VT) and QA coils • Different time scale of quenches in coil 13 • No clear evidence of systematic quench start in LE in latest quenches (coil 9 and 13) C 3 C 2 Lead End TQ Internal Review Nov 29 – Dec 1, 2006 8 10 TQC 01 test and analysis 40 39 27 11

Voltage Spikes Quench #37 Quench #1 Quench #63 TQ Internal Review Nov 29 –

Voltage Spikes Quench #37 Quench #1 Quench #63 TQ Internal Review Nov 29 – Dec 1, 2006 Quench #61 TQC 01 test and analysis 12

Questions and Answers … (in progress) 1. Why 4. 5 K plateau at 70%

Questions and Answers … (in progress) 1. Why 4. 5 K plateau at 70% of ssl? Low pre-stress, see following talk 2. Why quenches only where outer pole is not glued? Different behavior (glued/non_glued) with low pre-stress, see following talk 3. Why training improved at 1. 9 K? Seen also in Nb. Ti magnets, More efficient cooling, Different disturbance spectrum at higher forces? 4. Why outer layer quenches after #41? See next slide… TQ Internal Review Nov 29 – Dec 1, 2006 TQC 01 test and analysis 13

Possible explanation for quenches in coil 13 Facts: All quenches in Coil 13 started

Possible explanation for quenches in coil 13 Facts: All quenches in Coil 13 started in segment B 2 BSH 1 (outer layer mid-plane turn lead side) and “propagated” into the splice within 1 -10 ms Quench antenna showed start in NLE Some quenches showed large voltage spikes at the beginning of voltage rise (as #63) Max Iq at 1. 9 K was at 100 and 125 A/s The field in the midplane turn of the outer layer is lower than 4 T at 9 k. A Hypotheses: If the quenches are due to cable degradation, the degradation should be very large: 5 strands can carry more than 9 k. A at 4. 5 K 4 T (i. e. almost 2 k. A per strand) but we know that the stability threshold of TQC 01 strand is lower than 1 k. A Strands should quench because they reach their stability threshold TQ Internal Review Nov 29 – Dec 1, 2006 TQC 01 test and analysis 14

Quench Protection studies Heater delay time can be << 25 ms at I =

Quench Protection studies Heater delay time can be << 25 ms at I = 62% Issl ~23% ssl msec ~62% ssl QI vs. T measurement: I [A] QI [MIITs] 5000 9. 05 Temp [K] 340 K TQC 01 protection heater studies by using spot heaters to initiate the quench. TQ Internal Review Nov 29 – Dec 1, 2006 TQC 01 test and analysis 15

Magnetic Measurements New Magnetic Measurement system for VMTF: New DAQ system New low noise

Magnetic Measurements New Magnetic Measurement system for VMTF: New DAQ system New low noise cables New stepper motor with tooth belt connection to the shaft New rotational shaft A new 10 cm probe was built TQ Internal Review Nov 29 – Dec 1, 2006 TQC 01 test and analysis 16

List of measurements First TC – 4. 5 K Loop 20 A/s to 6.

List of measurements First TC – 4. 5 K Loop 20 A/s to 6. 5 k. A Second TC – 1. 9 K Z –scan at 4 k. A –magnetic center Loops, 20, 40 and 80 A/s up to 7. 0 k. A Accelerator profile – the same like LHC, IP=15 min Room temperature measurements Results: http: //www-td. fnal. gov/~velev/TQC/web_summaries/tqc 01/magnetic. Measurements/tqc_mag_meas. html TQ Internal Review Nov 29 – Dec 1, 2006 TQC 01 test and analysis 17

Geometrical harmonics, 20 A/s 81 cm, harm current TF errors 10 cm, harm errors

Geometrical harmonics, 20 A/s 81 cm, harm current TF errors 10 cm, harm errors 6. 4996 0 6. 997967 0 0. 013067 9. 05 E-05 0. 021271 0. 001153 b 3 -0. 05465 0. 214555 1. 399725 0. 308537 b 4 -0. 7912 0. 109108 -0. 9871 0. 027478 b 5 0. 171997 0. 083558 0. 437678 0. 023161 b 6 -0. 1386 0. 056922 -0. 30275 0. 030829 b 7 0. 017989 0. 048361 0. 053265 0. 009736 b 8 0. 026349 0. 023422 0. 000469 0. 014986 b 9 0. 057803 0. 050283 0. 001527 0. 007649 b 10 0. 040826 0. 023141 -0. 00484 0. 011168 a 3 -3. 36529 0. 089397 -1. 48833 0. 205239 a 4 -0. 02136 0. 086714 0. 465526 0. 272528 a 5 -0. 18511 0. 052458 -0. 02955 0. 016662 a 6 -0. 02802 0. 065699 -0. 01551 0. 0499 a 7 -0. 0592 0. 048854 0. 067873 0. 016052 a 8 -0. 02431 0. 065366 0. 010613 0. 012047 a 9 0. 00347 0. 043278 0. 012823 0. 015395 a 10 0. 02519 0. 04138 -0. 0032 0. 012897 TQ Internal Review Nov 29 – Dec 1, 2006 TQC 01 test and analysis 18

Magnetic Measurement Conclusions TQC 01 – accelerator quality in the body Sextupole ~ several

Magnetic Measurement Conclusions TQC 01 – accelerator quality in the body Sextupole ~ several units, a 3 ~ 2. 4 units Unexpected hysteresis is observed in the low level un-allowed harmonics, which depends on the ramp rate (eddy current? ) This effect is not present in the allowed dodecapole where it could be expected. Dynamic persistent current effects is not observed TQ Internal Review Nov 29 – Dec 1, 2006 TQC 01 test and analysis 19

TQC 01 Instrumentation Strain gauges: • Azimuthal gauges on coil inner surfaces near pole

TQC 01 Instrumentation Strain gauges: • Azimuthal gauges on coil inner surfaces near pole • Axial gauges at two positions on inner coil surface • Gauges on the control spacers. • Gauges on the exterior surface of the skin. • Gauges on the end preload bolts. 14000 N TQ Internal Review Nov 29 – Dec 1, 2006 14000 N TQC 01 test and analysis 20

End Bullets All bullets in contact after cooldown ~ Linear dependence vs. magn. force

End Bullets All bullets in contact after cooldown ~ Linear dependence vs. magn. force Small increase of rigidity at higher forces TQ Internal Review Nov 29 – Dec 1, 2006 TQC 01 test and analysis 21

Skin Gauges Reliable gauges Showed some increase of load at higher forces TQ Internal

Skin Gauges Reliable gauges Showed some increase of load at higher forces TQ Internal Review Nov 29 – Dec 1, 2006 TQC 01 test and analysis 22

Control Spacer Gauges Linear unloading of spacers at 4. 5 K Strange behavior at

Control Spacer Gauges Linear unloading of spacers at 4. 5 K Strange behavior at 1. 9 K Not compensated TQ Internal Review Nov 29 – Dec 1, 2006 TQC 01 test and analysis 23

Coil Longitudinal Gauges Small linear behavior (tension) at 4. 5 K Strange behavior at

Coil Longitudinal Gauges Small linear behavior (tension) at 4. 5 K Strange behavior at 1. 9 K Not compensated TQ Internal Review Nov 29 – Dec 1, 2006 TQC 01 test and analysis 24

Coil Azimuthal Gauges at 4. 5 K In glued area In nonglued area Not

Coil Azimuthal Gauges at 4. 5 K In glued area In nonglued area Not compensated A lot of things we don’t understand (Work in progress) TQ Internal Review Nov 29 – Dec 1, 2006 TQC 01 test and analysis Gauges at 1. 9 K 25

Conclusions • TQC 01 reached 9 k. A at 4. 5 K (70% ssl)

Conclusions • TQC 01 reached 9 k. A at 4. 5 K (70% ssl) and 12 k. A at 1. 9 K (85% ssl) 200 T/m gradient • Training quenches before #42 were limited to the inner layer pole turns in the straight section area where pole pieces were not glued to the coil • After reaching approximately 12000 amps at 1. 9 K, quenches moved to outer layers (coils 9 and 13) • Quench current at 4. 5 K after 1. 9 K testing was slightly lower than previous 4. 5 K results • Bullet and skin gauges gave reliable results in all conditions, gauges on control spacers and on coils gave mixed results (analysis in progress) TQ Internal Review Nov 29 – Dec 1, 2006 TQC 01 test and analysis 26