Domenico CAIAZZA
ESR2.1, WP2
Midterm Review
28-29/05/2015
 Bachelor’s degree in computer science engineering, University of
Sannio
 Thesis title: Control techniques for miniatures UAVs*
(* Unmanned Aerial Vehicle)
 Master’s degree cum laude in automation engineering, both at
University of Sannio
Background
 Thesis title: Measuring the longitudinal profile of magnetic fields by
vibrating wires
 Technical student at CERN for the thesis related project
 Artistic background
 Solfeggio and music theory diploma
 5th year piano diploma, conservatory of music “Nicola Sala”
(Benevento)
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
 Contract start date: 1st February 2014
 PACMAN subject:
 PhD title: Stretched-wire systems for the magnetic measurement of
small-aperture magnets
ESR2.1, WP2 /
Magnetic
measurements
 PhD Institution: University of Sannio
 Secondment: Sigmaphi, Metrolab
CERN Supervisors
Prof. Stephan RUSSENSCHUCK
Academic supervisors Prof. Pasquale ARPAIA
Industry supervisor
Marie-julie LERAY, Philip KELLER, Jacques TINEMBART
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
 Title Stretched-wire systems for the magnetic measurement of
small-aperture magnets
PhD thesis
 Start of date 1st June 2014
 Credits required / Already obtained 24/?
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
A single stretched wire
Magnetic
measurements
 field strength and
direction
 field harmonics
 magnetic axis
 longitudinal field
profile
State of the art /
Wire-based
transducers
Φ0.1 mm conducting wire (Cu-Be alloy)
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
 Measurement of integrated magnetic field strength
 The single stretched wire method as absolute reference for the LHC
magnets (precision in the order of 10-5) [1]
 Measurement of magnetic field quality
 Single stretched wire for high gradients ( 1̴ 3 Tm/m), large apertures ( ̴70
mm): precision of 5· 10-5 [2]
 Oscillating wire for low gradients ( ̴2 Tm/m), small apertures ( ̴20 mm):
repeatability within 4· 10-5, 5· 10-5 max difference with respect to rotating
coil measurement [3]
State of the art /
Literature
review
1 J.
Di Marco et al., “MTF Single Stretched Wire System”. Tech. Man., MTF-96-0001, 1996.
G. Le Bec et al., “Stretched wire measurement of multipole accelerator magnets”. Physical Review Special Topics Accelerators and Beams, 2012.
3 P. Arpaia et al., “Measuring field multipoles in accelerator magnets with small-apertures by an oscillating wire moved
on a circular trajectory”. JINST, Journal of Instrumentation, 2012.
2
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
 Localization of magnetic field axis
 Single stretched wire: 5 μm uncertainty for LHC quadrupoles (215 T/m
gradient) [4]
 Vibrating wire technique:
 10 μm repeatability on 12 T/m gradient, 67 mm aperture quadrupole [5]
 Repeatability better than 1 μm with Phase Locked Loop and 2 T/m gradient [6]
State of the art /
Literature
review
4 J.
Di Marco et al., “Field alignment of quadrupole magnets for the LHC interaction Regions”. IEEE Transactions on
Applied Superconductivity, 2000.
5 A. B. Temnykh, “The use of vibrating wire technique for precise positioning of CESR Phase III super-conducting
quadrupoles at room temperature, Proceedings of the 2001 Particle Accelerator Conference, 2001.
6 C. Wouters et al., “Vibrating wire technique and phase lock loop for finding the magnetic axis of quadrupoles”.
Applied Superconductivity, IEEE Transactions, 2012.
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
 Comparison on the same magnet and compatibility of single
stretched wire and vibrating wire magnetic axes
 Vibrating wire for measuring field strength
Research gap /
 Compensation of non uniform background fields
Wire-based
magnetic
measurements
 Uncertainty analysis / optimal measurement condition
 Inclusion of nonlinear effects, polarized motion, resonance
instability
 Axis transfer to the magnet frame
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
WP1 Metrology &
Alignment
H. Mainaud Durand
Project /
Claude
Solomon
WP2 Magnetic
Measurements
S. Russenschuck
Domenico
Giordana
WP3 Precision mech.
& stabilization
M. Modena
Iordan
Vasileios
Place in
PACMAN
Peter
WP4 Beam
Instrumentation
M. Wendt
Silvia
Natalia
David
“Stretched-wire systems for the magnetic measurement of small-aperture magnets”
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
 Development of a magnetic
measurement system based on
the vibrating wire fieldmeasuring method for small
aperture magnets
Project /
Objectives
 Performance
improvement/refinement of the
current state-of-the-art CERN
wire systems
 Integration in a common bench
for the simultaneous alignment
of main quadrupole and BPM
 Preparation of the system for industrialization
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
Start
•
•
Literature review
Metrological characterization of the existing, state-of-the-art, CERN wire-based
measurement system
Individuation of lacks/limitations
Project /
Technical
Theoretical
•
•
Method
followed
Investigation of nonlinear effects
Validation of assumptions
•
•
Wire vibration sensors
Mechanical stability (tension, environment)
Improvement/refinement of
techniques
Magnetic measurements: magnetic axis, field quality, field strength
• Comparison of different methods, define optimal measurement conditions, try new solutions
PACMAN bench design & validation
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
General tasks
Project /
•
•
•
Extension of mathematical model (nonlinearities, coupled motion)
Comparison of different wire vibration sensors (phototransistors, fiber optics, CCD)
Uncertainty analysis / optimal measurement configuration
Specific tasks
Tasks
description
Magnetic axis
• Comparison of different methods
 Single stretched wire vs vibrating wire
• Correction of effects from non homogeneous background fields
• Performance evaluation on CLIC MBQ at low gradient
• Transfer of magnetic axis to magnet frame
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
Specific tasks
Project /
Tasks
description
Magnetic field quality
• Comparison of different methods
 Single stretched wire vs vibrating wire
• Uncertainty analysis / optimal measurement configuration
• Measurement of oscillation profile by array of optical sensors
Magnetic field strength
• Calibration of the vibrating wire by opposition method
General tasks
• Hardware & software setup
• Validation campaign
• Inter-comparison with PCB rotating coils
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
Single stretched-wire method
• Metrological reference for integrated field strength, direction and magnetic axis of LHC
magnets
• Magnetic flux measurement
Project /
Background

J. Di Marco et al., “Field alignment of quadrupole magnets for the LHC
interaction Regions”. IEEE Transactions on Applied Superconductivity, 2000.
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
R
Vibrating-wire method
Wire in magnetic field
Plucked string
Feeding the wire by alternating current
(Lorentz Force)
Project /
Measure wire motion
amplitude X and Y components
Background
Relate motion to
magnetic field properties
A. Temnykh. “Vibrating wire field-measuring technique”. Nuclear Instruments and Methods in Physics Research, 1997.
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
Assumptions and mathematical model
 Linearity
 Plane motion
 Uniform and constant tension
Project /
 Small deflections
 Constant length
 Uniform mass distribution
Background
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
Measurement system design
Driving current frequency tuning
Resonances
Project /
Background
Working frequencies for max sensitivity
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
Background field & elliptic motion
 No magnet on the measurement
station
•
Project /
Experimental
characterization
Background fields
–
•
Elliptically polarized trajectory
–
in resonance condition
Predicted in:
J. A. Elliott. “Intrinsic nonlinear effects in vibrating strings”,
American Journal of Physics, 1989
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
2% alteration of first harmonic
Resonance instability
 Around resonance
 Non-constant oscillation amplitude!!!
 Effect depending on the excitation
frequency: minimal in resonance
condition (5%)
Project /
Possible reasons
•
Experimental
characterization
•
•
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
Non constant length
and/or tension
Non ideal clamping
(friction on the supports)
Excluded: coupling with
ground vibrations
Nonlinearity and overtones
main tone
Project /
overtones
Experimental
characterization
•
Overtone amplitude from 2% to 7% of the main
tone
–
•
Depending on system configuration
Overtones not contained in the current excitation
signal
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
Nonlinearity!
Comparison of SW and VW for measuring magnetic center
Method 2: vibrating-wire center
Method 1: stretched-wire center
Project /
x0 [mm]
sx [mm]
y0 [mm]
sy [mm]
x0 [mm]
sx [mm]
y0 [mm]
sy [mm]
-0.270
0.136
0.123
0.098
-0.272
0.003
0.086
0.004
stretched wire
vibrating wire
 Precision
Results
Center offset
 Compatibility
 30 times better for the vibrating wire (3-4 μm)
 Sensitivity
 Vibrating wire is suitable at low integral
gradient (< 0.2 T)
 Background fields
 Stretched wire not sensitive
 Compensation needed for vibrating wire
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
Background field correction
Developed a correction procedure for background field effects
• Suitable for strength adjustable magnets
• For non homogeneous field distributions
• Avoiding magnet rotation
Project /
Measuring at different magnet currents
actual center
apparent center
external field
magnet gradient
Fitting to the
model
Results
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
Axis localization of a CLIC Drive Beam quadrupole
 Magnetic axis measurement + fiducial
markers localization
•
In collaboration with EN-MEF-SU (Large
Scale Metrology Section)
 Both center and tilt were measured by the
vibrating wire
Project /
 Axis determination with 3 μm horizontal and
4 μm vertical precision
60
50
Results
CLIC DBQ (12 T integrated gradient) on the
fiducialization bench with vibrating wire system
40
30
20
Magnetic center as a function of the
magnet current
M. Duquenne et al., “Determination of the magnetic axis of a
CLIC drive beam quadrupole with respect to external alignment
targets using a combination of wps, cmm and laser tracker
measurements”. Proceedings of IPAC2014, Dresden, 2014.
x [μm]
10
y [μm]
0
-10 0
20
40
60
-20
-30
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
Magnet current
80 A
100
Uncertainty analysis
Configuration parameters
L/Lm, T, δ, WP, fexc
•
•
VW system
Project /
Performance
•
•
Repeatability (σ)
Sensitivity (s)
Sw , ϑs
Noise parameters
A linear model to relate the
performance to the parameters
Design of experiments (Taguchi)
Results
•
•
Choice of parameters and
range
Definition of performance
characteristic
Planning of experiments
Analysis
Experiment# L/Lm
1 5.3
2 5.3
3 5.3
4 10.14
5 10.14
6 10.14
7 20.4
8 20.4
…
…
T [g]
600
900
1100
600
900
1100
600
900
…
δ [V]
0.1
0.7
1.5
0.1
0.7
1.5
0.7
1.5
…
WP [V] sw [m/s] Δfexc [Hz]
5.7
0.3
0
6.1
0.15
-0.5
6.5
0.7
-1
6.1
0.15
-1
6.5
0.7
0
5.7
0.3
-0.5
5.7
0.7
-0.5
6.1
0.3
-1
…
…
…
ϑs
0
-5
-10
-10
0
-5
-10
0
…
performance mean
parameter effect
model uncertainty
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
Preliminary results for vibrating wire
Fitting to regression model
Analysis of variance (ANOVA)
Testing for differences between means
of the performance due to
parameters’ effect
Project /
Results on measurement of magnetic center by the vibrating wire
ANOVA results
pValue
L/Lm
T
δ
WP
sw
Δfexc
ϑs
Results
•
Significant effect of the wire vibration amplitude
- regulated by wire current supply
•
Next step: finding the optimal configuration
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
0.372990
0.242860
0.008936
0.304020
0.924160
0.635730
0.339430
Optical sensors for measuring wire vibration
Phototransistors
 cheap
 very sensitive
CMOS sensors
 linear
 wide range
(6mm)
Project /
Results
Fiber optics
 immune to magnetic
field
Need piezo-stages to hold the
working point
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
Characterization
Phototransistors
Fiber optics units
Project /
Results
Range:
Sensitivity:
̴ 0 μm
5
28.4 V/mm
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
Range:
Sensitivity:
̴ 0 μm
4
26.1 V/mm
Opposition method for the vibrating wire
In collaboration with A. B. Temnykh, Cornell University
20
dipole current [A]
15
measured quadrupole
reference dipole
10
Project /
5
integral field [r. u.]
0
0
5
10
15
20
25 mm
-5
Results
-10
Opposition method
 use a reference dipole to
compensate wire vibrations
•
•
•
Wire position
Repeatability of dipole current
measurement within 1·10-4
Applications: magnet quality and strength
Drawback: transfer function of the reference dipole not linear and must be known
accurately
Possible solutions: air-coils
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
30
 Metrology training (2 days at CERN)
 Main topics: introduction on history of metrology, definition of
measurement uncertainties, description of geometric tolerances,
interpretation of mechanical drawings, basic concepts of measurement
science (precision, accuracy …)
Training /
Network-wide
activities
 AXEL course – Introduction to particle accelerators (5 days at CERN)
 Main topics: beam transverse dynamics, magnets and their configuration,
resonances, longitudinal motion, synchrotron radiation, transfer lines,
injection and ejection, longitudinal and transverse beam instabilities
 PhD School – Seminario di Eccellenza “Italo Gorini” on “Measurements
and devices for the innovation and the technological transfer”, Lecce
(Italy), 1-5 September 2014
 Seminars concerning last theoretical developments of measurement
science and on some of the forefront technologies for the realization of
measurement devices for industry and society.
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
 Secondment in SIGMAPHI (2 months, Vannes)
Training /
 Training on use of digital integrators devices for magnetic measurements
 Setup of a measurement bench with search coil fluxmeter for a curved
dipole magnet for the FAIR project
 Measurement campaign by Metrolab PDI 5025 and the Metrolab FDI 2056
integrators
Local training
activities
Metrolab FDI 2056
FAIR HESR dipole in Sigmaphi
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
 Team building (1 day at CERN)
 Discussions on major aspects concerning working in a team and on
practical tasks to strengthen team spirit
 Making presentations (3 days)
Training /
 Design a presentation, improving non-verbal language (voice, body,
distance), design of visual aids, development of a personal style
Transferable
skills
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
Conferences & workshops:
 “22th IMEKO TC4 International Symposium and 18th International Workshop on
ADC Modelling and Testing Research on Electric and Electronic Measurement for the
Economic Upturn”
 Talk on vibrating wire method for longitudinal field profiles measurement with
introduction on PACMAN project.
 1st PACMAN Workshop
Outreach &
Dissemination
 Talk on wire methods for measuring magnetic axes and lab visit.
Others:
 Popscience – European Researchers’ night 2014
 Presentation of PACMAN ITN to general public at FNAC in Geneva, 26 September 2014.
 JUAS 2015 – Joint Universities Accelerator School
 Preparation of magnetic measurement exercises and demonstration for the practical
days at CERN of the JUAS students in the magnetic measurement laboratory. 26 and 27
February 2015.
 Teaching activity
 2 weeks at University of Sannio giving lectures on measurement and instrumentation
basics and practical exercises in the laboratory. 7-11 Apirl 2014, 20-24 Apirl 2015.
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
Industrial partner
Networking
Opportunities
Industrial partner
Academic partner
ESR 2.1
A. B. Temnykh
Magnetic measurement section
For measurements done in Sigmaphi
J. Di Marco
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
Because of
Impact




the quality of the technical and personal training
networking opportunity with scientific and industrial communities
facing with public
working in forefront research institute as CERN
I expect to be ready to work as a researcher in the European industry
And to contribute to community’s growth
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
Thank you for your
attention
Midterm Review
28-29/05/2015
SPARES
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
•
Sensors:
phototransistor Sharp
GP1S094HCZ0F
•
Current generator:
Keithley 6351
•
Common marble
support for magnets
and stages
P. Arpaia, M. Buzio, J. G. Perez, C. Petrone, S. Russenschuck, L. Walckiers.
“Measuring field multipoles in accelerator magnets with small-apertures by an oscillating wire moved on a circular trajectory”, JINST Journal of Instrumentation, 2012
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
Measurement method
• Measure the frequency response
– Vibration amplitude and phase
• Fit with the mathematical model
– Longitudinal field coefficients
• Calculate the longitudinal field profile
(by inverse Fourier transform)
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
Natural vibration modes
•
•
Reconstruction error 3% of the field
peak
Repeatability 2%
–
RMS difference
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
•
•
Bandwidth limitation
Uncertainty sources
Preliminary results
Fitting to regression model
Analysis of variance (ANOVA)
Testing for differences between means
of the performance due to parameters
effect
Results on measurement of magnetic center by the vibrating wire
Project /
ANOVA table
Estimate δk
SE
tStat
pValue
(Intercept) -0.10479 0.17082 -0.61349 0.55325
Results
L/Lm
T
δ
WP
-0.0013
-5.30E-05
0.04952
0.029118
0.001394 -0.9326 0.37299
4.27E-05 -1.2412 0.24286
0.015305 3.2356 0.008936
0.026874 1.0835 0.30402
sw
-0.00369
0.03781 -0.09763 0.92416
Δfexc
0.010502
0.0215
0.48849
0.63573
ϑs
0.002157
0.00215
1.0032
0.33943
SumSq
DF
MeanSq
pValue
L/Lm
T
δ
WP
0.001206
0.002136
0.014517
0.001628
1
1
1
1
sw
1.32E-05
1 1.32E-05 0.009532
0.92416
Δfexc
0.000331
1 0.000331
0.23863
0.63573
ϑs
0.001396
0.013867
1 0.001396
10 0.001387
1.0064
0.33943
Error
0.001206
0.002136
0.014517
0.001628
F
0.86975 0.37299
1.5406 0.24286
10.469 0.008936
1.174 0.30402
Significant effect of the wire vibration amplitude! (regulated by wire current
supply)
• Next step: finding the optimal configuration
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
Background field compensation
• Solution 1: displace the quadrupole at L/4
L
Project /
2 L
 2
B
sin

E

0
L
 L

z  dz  0

B
A
Z. Wolf. “A Vibrating Wire System For Quadrupole Fiducialization ”, Tech. rep. LCLS-TN-05-1. SLAC National Accelerator Laboratory, Menlo Park,
California, USA, 2005
 Solution 2: measure at different gradients
Results
A
B
 Q : oscillation from quad field
 E : oscillation from external dipole
 ( x)   Q ( x)   E
 k ( I 0 )  G  x  x0    E
x0' :  ( x0' )  0
x0'  x0 
Works if there is not a constant dipole in the magnet (not depending on Im)
Domenico CAIAZZA, ESR2.1
PACMAN Mid-term review 28-29/05/2015
E
k G