m.valentino, c. bonavolontà coherentia cnr -infm, naples, italy v. palmieri
DESCRIPTION
Magnetometry and Non Destructive Evaluation. M.Valentino, C. Bonavolontà Coherentia CNR -INFM, Naples, Italy V. Palmieri Istituto Nazionale Fisica Nucleare, Legnaro National Laboratories, Legnaro (PD), Italy. Outline:. Sensors for magnetometry - PowerPoint PPT PresentationTRANSCRIPT
The International Workshop on THIN FILMS APPLIED TO SUPERCONDUCTING RF AND NEW IDEAS FOR PUSHING THE LIMITS OF RF SUPERCONDUCTIVITY M. Valentino, Padova-Italy, October 9 – 12, 2006
M.Valentino, C. Bonavolontà Coherentia CNR -INFM, Naples, Italy
V. Palmieri
Istituto Nazionale Fisica Nucleare, Legnaro National Laboratories, Legnaro (PD), Italy
Magnetometry and Non Destructive Evaluation Magnetometry and Non Destructive Evaluation
The International Workshop on THIN FILMS APPLIED TO SUPERCONDUCTING RF AND NEW IDEAS FOR PUSHING THE LIMITS OF RF SUPERCONDUCTIVITY M. Valentino, Padova-Italy, October 9 – 12, 2006
Outline:
Sensors for magnetometry
Design of high sensitivity magnetic sensors working in unshielded environment
Giant Magneto Resistance (GMR) sensors
GMR devices for magnetic field detectors and Eddy-current measurements
Real time correlation between magnetic signal and corrosion on bulk Niobium
Real time magnetic detection of fatigue stress in metals
2D high sensitivity magnetic image
The International Workshop on THIN FILMS APPLIED TO SUPERCONDUCTING RF AND NEW IDEAS FOR PUSHING THE LIMITS OF RF SUPERCONDUCTIVITY M. Valentino, Padova-Italy, October 9 – 12, 2006
Magnetic field (Tesla)
Magnetic sensors & applications
10-4
10-5
10-6
10-7
10-8
T
10-9
10-10
10-11
nT
10-12pT
10-13
10-14
10-15fT
Magnetometer field resolution
Applications
NDE
Bio
mag
net
ic a
pp
lica
tio
ns
Hall
Flux-gate
HTS
LTS
GMR
corr
osi
on
Fat
igu
e
The International Workshop on THIN FILMS APPLIED TO SUPERCONDUCTING RF AND NEW IDEAS FOR PUSHING THE LIMITS OF RF SUPERCONDUCTIVITY M. Valentino, Padova-Italy, October 9 – 12, 2006
Main magnetic sensors characteristics
Sensor Range Temperature
stabilitySensitivity
(Unsh.Environment) Cost
Hall probe ± 10 mT low0.8 T /Hz @
1Hzlow
Flux Gate ± 70T low236 nT/Hz @
1Hzmedium
GMR ± 50 T high320 pT /Hz @
1Hzlow
SQUID ± 5T low176 pT/Hz @
1Hzhigh
The International Workshop on THIN FILMS APPLIED TO SUPERCONDUCTING RF AND NEW IDEAS FOR PUSHING THE LIMITS OF RF SUPERCONDUCTIVITY M. Valentino, Padova-Italy, October 9 – 12, 2006
GMR Sensors Principles
Alloy and base transition metal targets (Ni/Fe, Co/Fe, Co/Cr/Pt, Pt/Mn, Ta, Cu, Au)
Ferromagnet Co
Ferromagnet CoNon magnetic metal Cu
No external Magnetic Field
J JHigh Electrical Resistance
J JLow Electrical Resistance
Ferromagnet Co
Ferromagnet CoNon magnetic metal Cu
Applied external Magnetic Field
Giant Magneto Resistance, (1988)
The International Workshop on THIN FILMS APPLIED TO SUPERCONDUCTING RF AND NEW IDEAS FOR PUSHING THE LIMITS OF RF SUPERCONDUCTIVITY M. Valentino, Padova-Italy, October 9 – 12, 2006
R/R ~ 10%-20%
GMR Sensors Principles
Electrical resistance variation due to the magnetic field
The International Workshop on THIN FILMS APPLIED TO SUPERCONDUCTING RF AND NEW IDEAS FOR PUSHING THE LIMITS OF RF SUPERCONDUCTIVITY M. Valentino, Padova-Italy, October 9 – 12, 2006
magnetic field noise responses in magnetic unshielded environment
Comparison between magnetic field responses of magnetometer, 1st and 2nd order gradiometer
0.01 0.1 1 10 100 1000 100001E-13
1E-12
1E-11
1E-10
1E-9
1E-8
1E-7
1E-6
1E-5
2st grad
INFM 1st grad
INFM mag
B (
Tes
la)
Hz
The International Workshop on THIN FILMS APPLIED TO SUPERCONDUCTING RF AND NEW IDEAS FOR PUSHING THE LIMITS OF RF SUPERCONDUCTIVITY M. Valentino, Padova-Italy, October 9 – 12, 2006
m
r
b
2
1
z
1st order Radial gradiometer
m
r
b
2 1
z
1st order off axis gradiometer
m
r
b
2
1
z
1st order transverse gradiometer
Useful Gradiometers configuration
dz
dBzdx
dBzdz
dBx
m
r
b
3
1
b
2
z
2nd order transverse gradiometer
2
2
dz
Bd x
The International Workshop on THIN FILMS APPLIED TO SUPERCONDUCTING RF AND NEW IDEAS FOR PUSHING THE LIMITS OF RF SUPERCONDUCTIVITY M. Valentino, Padova-Italy, October 9 – 12, 2006
detector
reference
1
2
3 4
5
Experimental set-up. 1) Niobium disk; 2) Teflon vessel filled with 40ml of Acid solution; 3) Fluxgate magnetometers sensors housed in a Plexiglas holder: detector and reference magnetometers are in a first order gradiometer configuration; 4) Aluminium shields; 5) mu-metal shield.
Niobium Buffered Chemical Polishing
BCP Solution :-Hydrofluoric acid -Phosphoric acid
The International Workshop on THIN FILMS APPLIED TO SUPERCONDUCTING RF AND NEW IDEAS FOR PUSHING THE LIMITS OF RF SUPERCONDUCTIVITY M. Valentino, Padova-Italy, October 9 – 12, 2006
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5
0.1
1
112111.8111.6111.4111.2111 without solution
nT /(
Hz)
1/2
Hz
Niobium corrosionBCP 1:1:1 to BCP 1:1:2 increasing the H3PO4 percentage the magnetic signalIntensity increase
The International Workshop on THIN FILMS APPLIED TO SUPERCONDUCTING RF AND NEW IDEAS FOR PUSHING THE LIMITS OF RF SUPERCONDUCTIVITY M. Valentino, Padova-Italy, October 9 – 12, 2006
The average magnetic field is plotted versus etching rate.
0.2
0.3
0.4
0.5
0.6
0.7
0.8
1 1.5 2 2.5 3
Etching Rate [micron/min]
nT/H
z1/2
Niobium corrosion
The International Workshop on THIN FILMS APPLIED TO SUPERCONDUCTING RF AND NEW IDEAS FOR PUSHING THE LIMITS OF RF SUPERCONDUCTIVITY M. Valentino, Padova-Italy, October 9 – 12, 2006
Cell width
(mm)
w[g] at 4V
weighing
w[g] at 4V
field
w[g] at 7V
weighing
w[g] at 7V
field
8 0,012 0,011 0,025 0,048
16 0,023 0,020 0,035 0,020
24 0,05 0,032 0,13 0,035
lF
BMr
t
w
0
24
Corrosion rate
Corrosion Rate evaluationCorrosion Rate evaluation
According to Faraday law
cells 50 mm long
Not explained by Faraday law
The International Workshop on THIN FILMS APPLIED TO SUPERCONDUCTING RF AND NEW IDEAS FOR PUSHING THE LIMITS OF RF SUPERCONDUCTIVITY M. Valentino, Padova-Italy, October 9 – 12, 2006
Curve cathode
Magnetic field distribution
Flat cathode
Line-scan
0 20 40 60 80 100 120
2.10
2.45
2.80
3.15
3.50
ma
gn
etic
fie
ld (T
)
mm
flat cathode curve cathode
-40 -20 0 20 40
0.0
0.1
0.2
0.3
0.4
0.5
0.6
curr
ent
densi
ty (
A/m
m^2
)
mm
flat cathode curve cathode
nF
jStMw
Cells with different cathode geometries
Optimization of the Cu-polishing
Cells with different cathode geometries
Optimization of the Cu-polishing
The International Workshop on THIN FILMS APPLIED TO SUPERCONDUCTING RF AND NEW IDEAS FOR PUSHING THE LIMITS OF RF SUPERCONDUCTIVITY M. Valentino, Padova-Italy, October 9 – 12, 2006
GMR 2nd order gradiometer
GMR 2nd order electronic gradiometer. It detects the in plane magnetic field component reducing the environmental noise
1st GMR
2nd GMR
3th GMR
2nd order Radial gradiometer
m
r
b
3
1
b
2
z
2
2
dzBd x
The International Workshop on THIN FILMS APPLIED TO SUPERCONDUCTING RF AND NEW IDEAS FOR PUSHING THE LIMITS OF RF SUPERCONDUCTIVITY M. Valentino, Padova-Italy, October 9 – 12, 2006
GMR testing on the electropolishing
The solution used: 55% Phosphoric acid45% n-buthanol
Flux gate 1st order gradiometer imaging GMR 2nd order gradiometer imaging
The International Workshop on THIN FILMS APPLIED TO SUPERCONDUCTING RF AND NEW IDEAS FOR PUSHING THE LIMITS OF RF SUPERCONDUCTIVITY M. Valentino, Padova-Italy, October 9 – 12, 2006
5 mm
4 mm
GMR sensors for Eddy-current probe
Circular excitation coil to induce eddy current into the specimen
The International Workshop on THIN FILMS APPLIED TO SUPERCONDUCTING RF AND NEW IDEAS FOR PUSHING THE LIMITS OF RF SUPERCONDUCTIVITY M. Valentino, Padova-Italy, October 9 – 12, 2006
Back side
Surface
GMR Eddy current probe has been tested using a specimen of AL-Ti alloy with rivets and artificial slots
GMR Eddy Current probe testing
Slot 1 Slot 2Slot 1 Slot 2
The International Workshop on THIN FILMS APPLIED TO SUPERCONDUCTING RF AND NEW IDEAS FOR PUSHING THE LIMITS OF RF SUPERCONDUCTIVITY M. Valentino, Padova-Italy, October 9 – 12, 2006
50 mm
20 mm
Detection of sub- millimetric scratch on Niobium surface
20
m
m50 mm
Artificial sub millimetric scratches have been produced on the Nb surface
Test sample GMR imaging
The International Workshop on THIN FILMS APPLIED TO SUPERCONDUCTING RF AND NEW IDEAS FOR PUSHING THE LIMITS OF RF SUPERCONDUCTIVITY M. Valentino, Padova-Italy, October 9 – 12, 2006
Working frequency: 3MHz
50 mm
20 mm
Test sample Eddy Current induction coil imaging
50 mm
20
mm
Comparison with conventional Eddy current induction system
The International Workshop on THIN FILMS APPLIED TO SUPERCONDUCTING RF AND NEW IDEAS FOR PUSHING THE LIMITS OF RF SUPERCONDUCTIVITY M. Valentino, Padova-Italy, October 9 – 12, 2006
Physical etching of titanium surface
The International Workshop on THIN FILMS APPLIED TO SUPERCONDUCTING RF AND NEW IDEAS FOR PUSHING THE LIMITS OF RF SUPERCONDUCTIVITY M. Valentino, Padova-Italy, October 9 – 12, 2006
mm
mm
GMR Eddy current Probe detection
The International Workshop on THIN FILMS APPLIED TO SUPERCONDUCTING RF AND NEW IDEAS FOR PUSHING THE LIMITS OF RF SUPERCONDUCTIVITY M. Valentino, Padova-Italy, October 9 – 12, 2006
Magnetic field scanner to detect fatigue effect in metals
System characteristics Speed: 3mm/s (0-6/mm/s)
Spatial resolution: 0,1mm
Position Reproducibility : 0,05mm
Magnetic field signal Reproducibility 0.01%-5 0 5 10 15 20 25 30 35
-17,3
-17,2
-17,1
-17,0
-16,9
-16,8
-16,7
-16,6
-16,5
-16,4
-16,3
-16,2
-16,1
-16,0
-15,9
Riproducibilità tra due misure successive
Bx (T
)
Posizione (mm)
Prima Dopo
The International Workshop on THIN FILMS APPLIED TO SUPERCONDUCTING RF AND NEW IDEAS FOR PUSHING THE LIMITS OF RF SUPERCONDUCTIVITY M. Valentino, Padova-Italy, October 9 – 12, 2006
Detection of the localized Fatigue process in steelMonitoring the Magnetic field
… around the cut
0 20 40 60 80 100 1203,8
4,2
4,5
4,9
5,2
5,6
Campione P3; sensore fermo sull'apice del tagliorosso -carico; verde- scarico
Bx
(T
)
(Rif. carico) -20 0 20 40 60 80 100 120 140-18,2
-17,8
-17,5
-17,1
-16,8
-16,4
-16,1
Campione P3; sensore a 20 mm dall'apice del tagliorosso -carico; verde- scarico
Bx
(T
)
(Rif. carico)
…20 mm far from the cut
The International Workshop on THIN FILMS APPLIED TO SUPERCONDUCTING RF AND NEW IDEAS FOR PUSHING THE LIMITS OF RF SUPERCONDUCTIVITY M. Valentino, Padova-Italy, October 9 – 12, 2006
Sub-millimetric Magnetic field imaging
9,5 kN 0,0 kN
23 kN 0,0 kN
0,1 mm
0,1 mm
The International Workshop on THIN FILMS APPLIED TO SUPERCONDUCTING RF AND NEW IDEAS FOR PUSHING THE LIMITS OF RF SUPERCONDUCTIVITY M. Valentino, Padova-Italy, October 9 – 12, 2006
Surface plastic deformation imaging, preliminary results
GMR responses, spatial resolution: 50m
Magnetic field resolution: 1nT/Hz1/2
mm
mm
0,1 mm
The International Workshop on THIN FILMS APPLIED TO SUPERCONDUCTING RF AND NEW IDEAS FOR PUSHING THE LIMITS OF RF SUPERCONDUCTIVITY M. Valentino, Padova-Italy, October 9 – 12, 2006
Conclusions Emerging magnetic sensors, like GMR, allows to detect with high sensitivity the magnetic field produced during the following process:
The ongoing corrosion of the metals electropolished as Cu and Nb.
The Fatigue stress effects in steels.
2D magnetic field imaging of sub-millimetric defects and plastic deformation in metals with a spatial resolution better than 100 micron.
Development of GMR Eddy current probe
Detection of surface sub-millimetric defects and scratches with depth less than 0.1 mm in Niobium plate.
Detection of corrosion effect with a depth less than 100micron, due to Ion etching on Titanium surface.
ProspectiveDevelopment of magnetic sensors array to measure the magnetic field during the electropolishing process of metals on non- planar geometry.