Results of Magnetic Measurements on MQXC 02
L. Fiscarelli on behalf of TE/MSC/MM section
12.06.2014
1
Geneva, 12/06/2014
MAGNETIC MEASUREMENT
1
SECTION
Overview
 Introduction:
– Measurement system
– Measurement plan
 DC characterization
– Stair step cycle (load-line)
 Dynamic characterization
– Ramp-rate study
 Simulated machine cycle
– Repeatability and Decay / Snapback
 Comparison with ROXIE model (data provided by Per Hagen)
 Cold-warm correlation
 Measurement resolution
 Conclusions
Geneva, 12/06/2014
MAGNETIC MEASUREMENT
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The two setups
– Flexible software
Framework for Magnetic
Measurements (FFMM)
– PXI crate
– Fast Digital Integrator (FDI)
– Motor + encoder + slip-ring
units
– Large diameter rotating
shaft
Support tube
Geneva, 12/06/2014
R=45 mm
5 coils
MAGNETIC MEASUREMENT
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Measurement plan
 A short magnetic measurement campaign was requested (limited availability of
cryogenic test station)
 Minimal set of measurement cycles was planned (“standard program”)
– Stair-step (“load-line”)
– Ramp-rate study (10, 20, 40, 80 A/s)
– Simulated machine cycle 3x (plateau of 1000 s at 820 A and then PELP ramp)
 Problems with Power Converter (trips on high current plateaus) wasted some time
– Simulated machine cycle repeated only 2 times
Geneva, 12/06/2014
MAGNETIC MEASUREMENT
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Results: stair-step cycle
Stair-step cycle
14
12
10
kA
8
6
4
2
0
0
2000
4000
6000
s
8000
10000
12000
Stair-step cycle to measure the DC transfer function and DC field quality
 quench
 pre-cycle (ramp-up at 11 A/s up to 12.8 kA, plateau of 300 s, ramp-down at -11 A/s to 100 A)
 from 100 A to 12.8 kA and back with a total of 35 steps
 plateaus (140 s)
 linear ramps (11 A/s)
Geneva, 12/06/2014
MAGNETIC MEASUREMENT
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Results: stair-step cycle, TF
Transfer function
 Strong saturation
 -180 units on straight section
 -160 units on integral
9.6
x 10
DC TF on straight section
-3
DC TF integral length
0.0159
up
down
9.55
up
down
0.0158
Tm/m/A
T/m/A
9.5
9.45
0.0157
9.4
0.0156
9.35
9.3
0
2
4
Geneva, 12/06/2014
6
kA
8
10
12
14
0.0155
0
2
4
6
kA
8
10
12
14
MAGNETIC MEASUREMENT
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Results: stair-step cycle, allowed multipoles
DC b6 on straight section
30
ramp-up
ramp-down
10
0
-4
units of 10 at 40 mm
20
-10
-20
-30
-40
0
DC b10 on straight section
3
4
6
kA
8
10
12
14
DC b14 on straight section
1
ramp-up
ramp-down
ramp-up
ramp-down
units of 10 at 40 mm
2
-4
1
-4
units of 10 at 40 mm
2
0
0.5
0
-0.5
-1
-2
0
2
4
Geneva, 12/06/2014
6
kA
8
10
12
14
-1
0
2
4
6
kA
8
10
12
14
MAGNETIC MEASUREMENT
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Results: stair-step cycle, not allowed multipoles
DC b3 on straight section
0
ramp-up
ramp-down
-4
units of 10 at 40 mm
-0.5
-1
-1.5
-2
-2.5
-3
-3.5
0
DC b4 on straight section
-2
-3
-4
-1
-4
-5
-6
4
6
kA
8
Geneva, 12/06/2014
10
12
14
-7
0
8
10
12
14
0
-4
units of 10 at 40 mm
-0.5
2
kA
DC a 3 on straight section
ramp-up
ramp-down
-1
-4
units of 10 at 40 mm
0
0
-1.5
0
6
DC a 4 on straight section
ramp-up
ramp-down
0.5
4
units of 10 at 40 mm
1
2
ramp-up
ramp-down
-0.5
-1
-1.5
-2
2
4
6
kA
8
10
12
14
0
2
4
6
kA
8
10
12
MAGNETIC MEASUREMENT
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14
Results: ramp-rate study
Ramp-rate study cycle
14
12
10
kA
8
6
4
2
0
0
2000
4000
s
6000
8000
10000
Ramp-rate study cycle to measure the effect of eddy currents and cable coupling currents
 pre-cycle (ramp-up at 11 A/s up to 12.8 kA, plateau of 300 s, ramp-down at -11 A/s to 100 A)
 current cycles from 820 A to 12.8 kA and back
 different ramp rates (10, 20, 40, 80 A/s)
Geneva, 12/06/2014
MAGNETIC MEASUREMENT
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Results: ramp-rate study
9.6
x 10
Dynamic TF on straight section
-3
10 A/s
20 A/s
40 A/s
80 A/s
9.55
10 A/s
20 A/s
40 A/s
80 A/s
0.0158
Tm/m/A
T/m/A
9.5
Dynamic TF integral length
0.0159
9.45
0.0157
9.4
0.0156
9.35
9.3
0
2
4
6
kA
8
10
12
14
0.0155
0
2
4
6
kA
8
10
12
14
As expected very small effects of ramp-rate on TF and multipoles
Geneva, 12/06/2014
MAGNETIC MEASUREMENT
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Results: simulated machine cycle
14
Machine simulation cycle
12
10
kA
8
6
4
2
0
0
5000
s
10000
15000
Simulated machine cycles to measure multipoles in machine simulated conditions and the
contribution of the persistent current decay and snapback
 quench
 pre-cycle (ramp-up at 11 A/s up to 12.8 kA, plt of 300 s, ramp-down at -11 A/s to 100 A)
 plateau at injection current of 1000 s
 ramp to the nominal field with slow parabolic start (no exponential)
 repeated two times
Geneva, 12/06/2014
MAGNETIC MEASUREMENT
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Results: simulated machine cycle, repeatability
0.0158
Machine simulation cycle TF on integral length
20
Machine simulation cycle b6 on integral length
first ramp-down
first ramp-up
first injection plateau
second ramp-down
second ramp-up
second injection plateau
0.0157
units of 10 at 40 mm
10
first ramp-down
first ramp-up
first injection plateau
second ramp-down
second ramp-up
second injection plateau
0.0156
0.0155
0.0155
0.0154
0
1.5
5
-20
-30
0
15
4
6
0.6
kA
8
10
12
14
first ramp-down
first ramp-up
first injection plateau
second ramp-down
second ramp-up
second injection plateau
0.4
-4
-4
0
2
Machine simulation cycle b14 on integral length
first ramp-down
first ramp-up
first injection plateau
second ramp-down
second ramp-up
second injection plateau
0.5
-0.5
-1
-1.5
-2
0
-10
Machine simulation cycle b10 on integral length
1
units of 10 at 40 mm
10
kA
0
-4
0.0156
units of 10 at 40 mm
T/m/A
0.0157
0.2
0
-0.2
-0.4
-0.6
2
Geneva, 12/06/2014
4
6
kA
8
10
12
14
0
2
4
6
kA
8
10
12
14
MAGNETIC MEASUREMENT
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Results: simulated machine cycle, decay and snapback
0
-4
0.6
-4
units of 10 at 40 mm
0.8
0.4
0.2
1
400
600
s
800
1000
Deacay and snapback cycle b6 on integral length
-0.05
-0.1
-0.15
0
200
400
600
s
800
-4
0.2
Geneva, 12/06/2014
840
1200
first cycle
second cycle
0.4
820
1000
Deacay and snapback cycle b10 on integral length
first cycle
second cycle
0.6
0
800
first cycle
second cycle
-0.2
0
1200
-4
units of 10 at 40 mm
0.8
200
units of 10 at 40 mm
0
0
Deacay and snapback b10 on integral length
first cycle
second cycle
units of 10 at 40 mm
1
Deacay and snapback b6 on integral length
A
860
880
900
-0.05
-0.1
-0.15
-0.2
800
820
840
A
860
880
900
MAGNETIC MEASUREMENT
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Comparison with ROXIE model
3.90E-04
 Transfer Function
Model
TF (T/m/A)
3.85E-04
– -25 units measured on geometric
Measurements
– Exact match for saturation
3.80E-04
 b6
– Good agreement
3.75E-04
 b10
3.70E-04
0
2000
4000
6000
8000
Current (A)
10000
12000
14000
– Constant offset
40
4
Model
2
Measurements
0
b10 (units)
b6 (units)
20
0
-2
Model
-4
Measurements
-6
-20
-8
-10
-40
0
2000
4000
6000
8000
Current (A)
10000
12000
14000
0
2000
4000
6000
8000
10000
12000
14000
Current (A)
* data provided by Per Hagen
Geneva, 12/06/2014
MAGNETIC MEASUREMENT
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Multipoles at 1.9 K and 5 kA (units at 40 mm)
Cold-warm correlation of multipoles
10
Cold - Warm correlation for multipoles
5
y = 0.91*x - 0.018
0
bn
-5
an
linear
-10
-10
-5
0
5
Multipoles at 300 K and 20 A (units at 40 mm)
10
Multipoles at 1.9 K are smaller than at 300 K
 Correlation factor of 0.91
 Elastic deformation ???
Geneva, 12/06/2014
MAGNETIC MEASUREMENT
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Multipoles (units at 40 mm)
Measurement precision
Measurement resolution
10
1
10
0
10
-1
bn at 1.9 K
an at 1.9 K
10
bn at 300 K
-2
an at 300 K
10
(Rref/Rcoil)k*n
-3
2
4
6
8
10
12
Harmonic order
14
16
High precision measurement results
 better than 0.01 units at 40 mm on multipoles
 ±5 units on TF
Geneva, 12/06/2014
MAGNETIC MEASUREMENT
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Conclusions
 Complete MM test campaign at cryogenic temperature on MQXC 02
 Saturation
 Low ramp-rate dependency
 Decay and snapback as expected
 High precision results both on TF and multipoles
 Disagreement model/measurements on TF solved
Geneva, 12/06/2014
MAGNETIC MEASUREMENT
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Appendix
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MAGNETIC MEASUREMENT
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Appendix 1: Correction of thermal contraction of shaft at 1.9 K
Material Properties: G-10 CR (Fiberglass Epoxy) [1]
We range from 300 K to 1.9 K
 thermal coefficient is ‘a’
A coil is a 3D object (width, length, radius)
 anormal * awarp * awarp → -1.21 %
[1] http://cryogenics.nist.gov/MPropsMAY/G-10%20CR%20Fiberglass%20Epoxy/G10CRFiberglassEpoxy_rev.htm
Geneva, 12/06/2014
MAGNETIC MEASUREMENT
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Appendix 2: Parameterization of Transfer Function
3.82
B2geom   I
x 10
3.8
T/m/A
B2def   I 2
B2sat   0  I , I 0 , I 0  I
3.78
3.76
3.74
[2] L. Bottura, Standard Analysis Procedures for Field Quality
Measurement of the LHC Magnets - Part II: Transfer Functions and
Parameterization
6
x 10
3.72
0
Model - Measurements residuals
-4
2
4
6
kA
8
10
12
14
8
10
12
14
Model
0
dTF/TF (units)
2
dTF/TF
Model (geometric, elastic, saturation)
Measurements
50
4
0
-2
-4
-50
-100
-150
Elastic deformation
Iron yoke saturation
-200
-6
-8
0
Transfer function
-4
2
4
Geneva, 12/06/2014
6
kA
8
10
12
14
-250
0
2
4
6
kA
MAGNETIC MEASUREMENT
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