at 65 TeV and beyond Arjan Verweij TEMPEPE on behalf of the MP3 cernchMP3 acknowledgments to everybody involved in magnet reception tests powering tests and operation ID: 652118
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Magnet Circuit performance at 6.5 TeV… and beyondArjan Verweij, TE-MPE-PEon behalf of the MP3 (cern.ch/MP3)acknowledgments to everybody involved in magnet reception tests, powering tests, and operation and analysis of the magnet circuits
Arjan Verweij, LHC Performance Workshop, 25-28 Jan 2016
2
Mera peak, 6.5 km high
Kun, 7 km highSlide3
Arjan Verweij, LHC Performance Workshop, 25-28 Jan 20163Overview of the magnet circuits from an operational point of view, with
focus on quenches,
excluding issues presented by Felix (shorts, ELQA, ...), Reiner (QPS), and Bernhard (beam-induced quenches w.r.t. BLM thresholds).
Feasibility of operation at 7 TeV
, based on training behaviour of previous HWC campaigns.I will not discuss the origin/understanding of quenches, de-training, memory,
etc; see website of QBT (Quench Behaviour Team
)
.
Useful links:
cern.ch/MP3/SummaryIssues List of all issues cern.ch/MP3/QuenchDatabase Database of all training quenches
OutlineSlide4
Arjan Verweij, LHC Performance Workshop, 25-28 Jan 20164DateDescription
2007/8Initial
HWC. Target: 7 TeV (12 kA)
Sept 2008Accident in S34Repair
nQPS installed. Warm-up of S12, S34, S45, S56, S67 to 300 K. Warm-up of S23, S78 and S81 to 80 K. tRB reduced to 51 s,
tRQ reduced to 9 s. 2009
HWC
to 3.5
TeV
(6 kA)Begin 2011HWC after Xmas to 3.5 TeVBegin 2012HWC after Xmas to 4 TeV (6.85 kA)Feb 2013
Powering tests to 7
TeV
(except mains)
2013-2014LS1. Warm-up of all sectors to 300 K. tRB back to 102 s, tRQ back to 30 s9/2014-3/2015HWC to 6.5 TeV (11.1 kA)Mar 2016HWC after Xmas to 6.5 TeV
Run1
Run2Slide5
Global view of training quenchesArjan Verweij, LHC Performance Workshop, 25-28 Jan 20165
Nr. of magnets
2008
2009Feb 2013
2014/560 A
75223
0
23
80-120 A
14763738423120 A triplet
40
0
1
04600 A6518140077154600 A triplet56
2641437
IPD18
13010
4IPQ
220490
68
31
IT mains
32
0042RQ794 2002RB1232 (twin aperture)30(S56 to 11.2 kA)00175(all sectors to 11.1 kA)
Important:
some commissioning currents and test sequences have been changed during the years, so the number of quenches cannot always be directly compared among HWC campaigns.Slide6
Arjan Verweij, LHC Performance Workshop, 25-28 Jan 2016660 A circuits
Nr. of magnets
2008
2009Feb 2013
2014/560 A7522
3023
5
quenches in 5 different magnets
Possibly not all quenches registered
23 quenches in 21 different magnets2 quenches on flat-top (60 A)Small number of quenches considering large number of magnets, and all quenches well above the operational currents.
Other issues:
2 circuits condemnedSlide7
Arjan Verweij, LHC Performance Workshop, 25-28 Jan 2016780-120 A circuitsSome retraining after thermal cycling.3 out of 4 triplet quenches due to additional 5 A margin.
Nr
. of magnets
2008
2009Feb 2013
2014/580-120 A1476
37
38
4
22120 A triplet400104RCO
16x77=1232
0
0
01Other issues: nominal current of 4 circuits reduced to 20-50 A4 triplet circuits condemnedSmall number of quenches considering large number of magnets.Slide8
600 A circuitsArjan Verweij, LHC Performance Workshop, 25-28 Jan 20168Circuit
# of magnets
Magnet
20082009
Feb 20132014/5
RCD16x77=1232MCD40
0
3
16
RCS16x154=2464MCS15038+1ROD/F
332
MO
2
006+1RQ648MQTLH2005RQS64MQS3
068+2
RQT12/1364MQT20
075+2
RQTD/F32x8=256MQT
21035
39+13
RQTL7-11
72
MQTLI
2901723+4RSD/F688MS4069+1RSS64MSS1003RU2MU3
0
0
8
Significant retraining after LS1, especially for RQTD/F and RQTL circuits.
Other issues:
RSS.A34B1, RCS.A78B2 condemned. 9 circuits with less magnets. 35 circuits with reduced nominal current.Slide9
600 A circuits - tripletsArjan Verweij, LHC Performance Workshop, 25-28 Jan 20169Circuit
# of magnets
Magnet
20082009
Feb 20132014/5
RQSX38MQSX
1
0
0
16+2RCBX *48MCBX2541419
Significant retraining after LS1.
Other issues:
Combined MCBX H-V powering imposes some constraints
*: not including the quenches due to combined powering600 A circuits:Many circuits to be closely watched in upcoming HWC campaigns.Slide10
IPD circuitsArjan Verweij, LHC Performance Workshop, 25-28 Jan 201610
Nr. of magnets
2008
2009Feb 2013
2014/5IPD1813
0104
Nr
. of magnets
2008
Feb 2013
2014/5
RD1
4 x MBX (1.9 K)
5800 A: 05800 A: 05450 A: 0RD24 x MBRC (4.5 K)4400 A: 04400 A: 04150 A: 0RD24 x MBRC (4.5 K)6000 A: 76000 A: 05650 A: 0RD3
4 x MBRS (4.5 K)5860 A: 65860 A: 9
5550 A: 2RD42 x MBRB (4.5 K)6150 A: 0
6150 A: 15850 A: 2
RD4.L4 and RD4.R4 quenched once in 2014/5, within 100 A of nominal.
Other issues:
RD1.R8 operates with one quench heater.Slide11
Arjan Verweij, LHC Performance Workshop, 25-28 Jan 201611RD3.L4Worrying in 2013 but trained quickly in 2014/5 (up to a reduced current of 5550 A).Slide12
IPQ circuitsArjan Verweij, LHC Performance Workshop, 25-28 Jan 201612Circuit
# of magnets
Magnet
Temp[K]
I_tr[A]2008
Feb 2013
I_tr
[A]
2014/5
RQ428MQY4.5
3610
9
7
34500RQ516MQY4.53610
18
34500RQ6
4MQY
4.53610
20
3450
0
RQ5
16
MQM4.543101723410014RQ624MQM4.54310
15
25
4100
14
RQ7
36
MQM
1.9
5390
1
2
5250
3
RQ8
24
MQM
1.9
5390
2
1
5100
0
RQ9
48
MQM
1.9
5390
2
2
5100
0
RQ10
24
MQM
1.9
5390
0
0
5100
0
Other issues:
RQ9 and RQ10 frequently trip due to thunderstorms and other external pick-ups
RQ8, RQ9, and RQ10 trip when the MB in positions A8, B8, A9, B9, A10 or B10 quenches.Slide13
Arjan Verweij, LHC Performance Workshop, 25-28 Jan 201613Quench behaviour is closely monitored over time, see MP3 meeting dd 14/10/2015 (S. Le Naour).Slide14
Nr. of magnets20082009
Feb 20132014/5
IT mains
32004
2IT-mains circuits
Arjan Verweij, LHC Performance Workshop, 25-28 Jan 201614
3 x RQX.L2 (Q1)
1 x RQX.R2 (Q2)
1 x RQX.L8 (Q3)
1 x RQX.L5 (Q3)Other issues:One training quench during operation in RQX.L2 (Q1) at 6760 ASlide15
Nr. of magnets20082009
Feb 20132014/5
RQ
794200
2RQ circuits
Arjan Verweij, LHC Performance Workshop, 25-28 Jan 201615
10899 A (28R4)
11280 A (14R5)
No training quenches during operation
10550 A (26L5)10363 A (15L1)Slide16
RB circuits: OutlineArjan Verweij, LHC Performance Workshop, 25-28 Jan 201616Reception acceptance tests in SM-18 (2002-2007)1st cool-down
2nd cool-down
HWC 2008: training of S56 to 11.2 kAHWC 2014/5: training of all sectors to 11.1 kA (6.5
TeV equiv.)Forecast for 7 TeV as presented by E. Todesco in MSC-TM (7 Jan 2016) and LMC (20 Jan 2016).
Other issues: In 3 dipoles, a high-field quench heater is replaced by a low-field one.Slide17
Arjan Verweij, LHC Performance Workshop, 25-28 Jan 201617Reception test (2002-2007) – 1st cool-down
Firm-1
Firm-2
Firm-3
All
# magnets400
420
412
1232
#Q to 12000 A321593450
1364
#Q to 11080 A
47
183183413Firm-3Firm-1Firm-2Cumulative plot of all quenches per firm, sorted by quench currentSlide18
Arjan Verweij, LHC Performance Workshop, 25-28 Jan 201618Reception test (2002-2007), 2nd cool-down
Firm-1
Firm-2
Firm-3
All
# magnets
33
55
28
116#Q to 12000 A1
st
cool-down
73
140772902nd cool-down113415
60#Q to 11850 A
1st cool-down54119
67240
2nd cool-down6
211037
#Q to
11080 A
1
st
cool-down43430682nd cool-down13486.5 x faster
8
.5 x
faster
Magnets
from all 3 firms
show a good “memory” when tested a few weeks later, after a thermal cycle.
Based on these data, the
nr
. of quenches
to reach 7
TeV
in
the LHC was estimated to be about
160
(P
.
Xydi
, A.
Siemko
, 2009)
.
4.8 x
fasterSlide19
Arjan Verweij, LHC Performance Workshop, 25-28 Jan 201619HWC 2008 – S56 to 11.2 kA30 quenches in 29 different magnets (2x Firm-2, 27x Firm-3).19 out of 27 quench values are
lower than the first quench during reception.One detraining quench.
Firm-3 magnets clearly behave differently as compared to Firm-1 and Firm-2, and w.r.t. to expectations based on “memory” observed during 2nd
cooldown of the reception tests. Based
on a simple
exponential fit, and weighting for large percentage of Firm-3 magnets in S56 (55%), reaching 10.98 kA (6.5 TeV
) in 8 sectors was expected to require 84 training
quenches, and about 30 more when adding a margin of 100 A.
“…. one should expect about 1000 quenches to reach 7
TeV. This number is however very approximate and a better estimate can only be made after at least one sector has trained to 7
TeV
.”
(A.
Verweij, Chamonix 2009)Slide20
Arjan Verweij, LHC Performance Workshop, 25-28 Jan 201620LHC – 8 sectors (2015)175 training quenches, quite a bit more than expected
.Slide21
Arjan Verweij, LHC Performance Workshop, 25-28 Jan 201621LHC – 8 sectors (2015)About 8x faster (as expected)
Only 1.3x faster
Cumulative plot of all quenches per firm, sorted by quench current
Extrapolation to 7
TeV
(12 kA) very tricky
6.5 TeV + marginSlide22
Arjan Verweij, LHC Performance Workshop, 25-28 Jan 201622Some interesting observationsS56: (containing 28 x Firm-1, 42 x Firm 2, 84 x Firm-3)2008: 24 quenches to reach 11080 A (2 x Firm-2, 22 x Firm-3). 15 out of
22 quenched below the 1st quench during reception
. 30 quenches to reach 11.2 kA.2014/5
: 16 quenches to reach 11080 A (all in Firm-3). 10 out of 16 quenched below the 1st quench during reception.24 of
the 27 Firm-3 magnets that quenched in 2008, did not quench again in 2014/5.
All sectors:
Nr
of quenches
Nr
of different magnets that quenched at least onceCases for which the 1st
quench during
HWC is lower than the 1
st quench during receptionFirm-1554 (80%)Firm-2272717 (63%)Firm-3143
13297 (73%)
No clear correlation between training during reception and in the LHC. The average quench value of the “2nd and 3rd
quenches” is 10828 A.Slide23
Arjan Verweij, LHC Performance Workshop, 25-28 Jan 201623Conclusions on the observed training as presented by E. Todesco (LMC, 20/1/2016)Differences in quench behaviour of the Firm-3 magnets along the production are statistically significant. (See also G. Willering, LMC, 8/4/2015)
Quench data are compatible with a scenario where at each warm-up we start in the same condition as at the beginning of the previous training.Quench data of Firm-3 are compatible with a partial but small preservation of memory.
Quench results in S56 (comparison 2008 with 2015/5) are compatible with magnets belonging to the same production (no bad or good magnets). No evidence of magnets to be removed in LS2.A good fraction of HWC data are compatible with Gaussian distribution for the first quench.Slide24
Arjan Verweij, LHC Performance Workshop, 25-28 Jan 201624Required training to reach 7 TeV as presented by E. Todesco (LMC, 20/1/2016)Possible strategy: push S12 and S45 to 7
TeV before LS2.S12: to see the behaviour of the Firm-1 and Firm-2 magnets
S45: to see possible “2nd quenches” in the Firm-3 magnets.
These two sectors require the lower number of quenches, so maximising information while minimising risk.
The upper bound for the number of “2
nd
quenches” is 150.Slide25
Arjan Verweij, LHC Performance Workshop, 25-28 Jan 201625Training quenches during operation in 2015
5
training quenches occurred at 10980 A, all in Firm-2 magnets
(14/5, 11/6, 9/7, 19/9,
3/11
)
1 May 2015
15 Dec 2015Slide26
Conclusions (operation at 6.5 TeV)Arjan Verweij, LHC Performance Workshop, 25-28 Jan 201626HWC 2014/5: Reaching 6.5 TeV required a significant number of training quenches, mainly in some 600 A circuits, some MQM magnets, and in the RB circuits. Some magnets/circuits train slower than in previous campaigns. The QBT should look into these cases to assess the long-term behaviour.
Operation 2015: Only a few training quenches were observed, showing that the additional current margins during HWC are correct
.
Powering tests March 2016: We will ramp all magnet circuits to the same values as during the campaign of 2014/5. We expect some quenches but this should not impact the planned duration of the tests.Some QPS thresholds will be reduced to be better protected in case of almost symmetric quenches in the high current circuits.
The RB circuits will be cycled to 10980+100 A with a plateau of at least 4 hrs. Depending on the number of training quenches during operation, we might recommend to repeat such a test at regular intervals (e.g. before each TS).Operation 2016: We expect smooth operation of the magnet circuits.Slide27
Conclusions (towards 7.0 TeV)Arjan Verweij, LHC Performance Workshop, 25-28 Jan 201627There is no indication that one or more high-current circuits could not be operated at 7 TeV, even though some magnets/circuits seem to train slower than in the past.
Commissioning time to 7
TeV would be dominated by the MB training. Estimates by E. Todesco show that another 270 training quenches are needed
plus an unknown number of second quenches for which an upper bound of 150 is given, plus an additional 170 if the training is preceded by a thermal cycle. A proper number for the entire machine can be given by training S12 and S45 to 7 TeV
, which would require about 2 weeks. Training of all 8 sectors can be performed in parallel, with a rate of about 120-160 quenches per week.
Possibilities to speed up the time for commissioning should be looked at (see also presentation R. Schmidt).
Each quench implies a certain risk (heater failure, inter-turn short, short-to-ground, pressure-related damage,
etc
), and a proper risk analysis should be performed before starting such a long training campaign. Slide28
AnnexArjan Verweij, LHC Performance Workshop, 25-28 Jan 201628Slide29
Arjan Verweij, LHC Performance Workshop, 25-28 Jan 201629Firm-3 quench behaviour along productionSlide30
Arjan Verweij, LHC Performance Workshop, 25-28 Jan 201630Statistics on the LHC main dipole quench heater firing for 2014-2015Since October 2014 (QPS-IST included):
2533 full charge firings in totalabout 1660 firings at zero current
Since April 2015 (1
st beam in the machine):247 full charge firings in total
about 175 firings at zero currentB15R8
C14R8A15R8
B14L6
A21L5
A8L2
A8L7A10L7
B8L4