μ μ S G S G Università Università degli degli Studi Studi di di Catania Catania Facoltà Facoltà di di Ingegneria Ingegneria Dipartimento Dipartimento di di Ingegneria Ingegneria Elettrica Elettrica Elettronica Elettronica e e dei dei Sistemi Sistemi Residence Times Difference (RTD) Residence Times Difference (RTD) - Fluxgate Fluxgate Magnetometer Magnetometer Ing Ing . Carlo Trigona . Carlo Trigona A.A. 2007/2008 μ μ S G S G Outline Outline 9Classification of magnetometers Classification of magnetometers 9Magnetometers for biomedical applications Magnetometers for biomedical applications 9RT RT- Fluxgate Fluxgate 9Working principle Working principle 9Expressions of RTD and Sensitivity Expressions of RTD and Sensitivity 9Fluxgate technology Fluxgate technology 9PCB FR4 PCB FR4 9“Wire” “Wire” 9 Magnetic particles and Magnetic particles and biosystems biosystems 9Set Set- up up 9Results Results 9 Volcanic ash detection Volcanic ash detection 9Set Set- up up 9Results Results 9Conclusion Conclusion Carlo Trigona A.A. 2007 Carlo Trigona A.A. 2007- 2008 2008
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Residence Times Difference (RTD) - Fluxgate · PDF fileResidence Times Difference (RTD) - Fluxgate Magnetometer ... 2 3 4 5 6 7 8 9 10 ... “wire ” technology can be used
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Carlo Trigona A.A. 2007Carlo Trigona A.A. 2007--20082008
µµS GS GRTDRTD--FluxgateFluxgate
The principle of RTD Fluxgate is to exploit the information carrThe principle of RTD Fluxgate is to exploit the information carried by the time ied by the time position of spikes in the position of spikes in the VoutVout signal. Time intervals, signal. Time intervals, T+T+ and and TT--, defined by two , defined by two successive peaks represent times spent by the core magnetizationsuccessive peaks represent times spent by the core magnetization in the two in the two steady states. These time intervals are called Residence Times. steady states. These time intervals are called Residence Times. The Residence The Residence Time Difference is the quantity RTD=Time Difference is the quantity RTD= T+T+ -- TT--. .
Carlo Trigona A.A. 2007Carlo Trigona A.A. 2007--20082008
µµS GS GRTDRTD--FluxgateFluxgateIfIf wewe considerconsider the the timestimes: t: t11, t, t22, t, t33, , it’it’s s possiblepossible toto writewrite::
( )( )
τ+=−=+
=+
13
22
11
:
:
tt
HtHHt
HtHHt
CeX
CeX
WrtingWrting the the equationsequations in the case of a in the case of a sinusoidalsinusoidal biasbias signalsignal of of amplitudeamplitudeand and frequencyfrequency wewe obtainobtain::
eHτ1
( )
CeX
CeX
HtHH
HtHH
−=⎟⎟⎠
⎞⎜⎜⎝
⎛⎟⎠⎞
⎜⎝⎛ −−
=+
2sinˆ
sinˆ
2
1
τω
ω
InvertingInverting the the functionsfunctions andand
wewe havehave the the expressionsexpressions::
( )1sin tω ⎟⎟⎠
⎞⎜⎜⎝
⎛⎟⎠⎞
⎜⎝⎛ −
2sin 2
τω t
Carlo Trigona A.A. 2007Carlo Trigona A.A. 2007--20082008
µµS GS GRTDRTD--FluxgateFluxgate
τω
τω
ω
+⎟⎟⎠
⎞⎜⎜⎝
⎛ −=
+⎟⎟⎠
⎞⎜⎜⎝
⎛ +=
⎟⎟⎠
⎞⎜⎜⎝
⎛ −=
e
XC
e
XC
e
XC
H
HHt
H
HHt
H
HHt
ˆarcsin
1
2ˆarcsin
1
ˆarcsin
1
3
2
1
2ˆarcsin
ˆarcsin
1
2ˆarcsin
ˆarcsin
1
23
12
τω
τω
+⎥⎥⎦
⎤
⎢⎢⎣
⎡⎟⎟⎠
⎞⎜⎜⎝
⎛ +−⎟⎟⎠
⎞⎜⎜⎝
⎛ −=−=
+⎥⎥⎦
⎤
⎢⎢⎣
⎡⎟⎟⎠
⎞⎜⎜⎝
⎛ −−⎟⎟⎠
⎞⎜⎜⎝
⎛ +=−=
−
+
e
XC
e
XC
e
XC
e
XC
H
HH
H
HHttT
H
HH
H
HHttT
The The expressionsexpressions of Residence Time of Residence Time differencedifference and and SensitivitySensitivity are:are:
⎥⎥⎦
⎤
⎢⎢⎣
⎡⎟⎟⎠
⎞⎜⎜⎝
⎛ −−⎟⎟⎠
⎞⎜⎜⎝
⎛ +=−= −+
e
XC
e
XC
H
HH
H
HHTTRTD
ˆarcsin
ˆarcsin
2
ω
⎥⎥⎥⎥⎥
⎦
⎤
⎢⎢⎢⎢⎢
⎣
⎡
⎟⎟⎠
⎞⎜⎜⎝
⎛ −−
+
⎟⎟⎠
⎞⎜⎜⎝
⎛ +−=
∂∂
=22
ˆ1
ˆ/1
ˆ1
ˆ/1
2
e
e
e
e
H
HxHc
H
H
HxHc
H
RTDHx
Sω
Carlo Trigona A.A. 2007Carlo Trigona A.A. 2007--20082008
The Automatic calibration system has been implemented with a set of instrument driven by labview
The RTD has been calculated by post elaborate the output signals with MatLab
Carlo Trigona A.A. 2007Carlo Trigona A.A. 2007--20082008
µµS GS G
““wirewire ” ” technologytechnology can can bebe usedusedtoto localizelocalize micromicro--entitiesentities and and ““punctualpunctual” ” magneticmagnetic fieldfield
Carlo Trigona A.A. 2007Carlo Trigona A.A. 2007--20082008
11µµll
NN
NNSS
SS
1µl spot
ExperimentalExperimental SetSet--upup (II) (II)
MagneticMagnetic particlesparticles forfor DNA DNA sequencingsequencing
µµS GS G
Carlo Trigona A.A. 2007Carlo Trigona A.A. 2007--20082008
ExperimentalExperimental SetSet--upup (II) (II)
Glass support for fluxgate coils
µµS GS G
Carlo Trigona A.A. 2007Carlo Trigona A.A. 2007--20082008
ResultsResults µµS GS G
The experiment has been conduced by taking several observations The experiment has been conduced by taking several observations of the of the fluxgate output for various spot sizes (obtained via the depositfluxgate output for various spot sizes (obtained via the deposition of ion of different known fluid volumes ranging from 0.5different known fluid volumes ranging from 0.5µµl to 4l to 4µµl). Each spot is l). Each spot is maintained in the measuring position for 300 seconds. maintained in the measuring position for 300 seconds.
Carlo Trigona A.A. 2007Carlo Trigona A.A. 2007--20082008
ResultsResults µµS GS G
RTD variation RTD variation obtained via the deposition of different known fluid obtained via the deposition of different known fluid volumes ranging from 0volumes ranging from 0µµl to 4l to 4µµl.l.
Carlo Trigona A.A. 2007Carlo Trigona A.A. 2007--20082008
ExperimentalExperimental SetSet--upup (III) (III)
System System forfor volcanovolcano particlesparticles detectiondetection
MagneticMagnetic particlesparticles
µµS GS G
Carlo Trigona A.A. 2007Carlo Trigona A.A. 2007--20082008
ExperimentalExperimental SetSet--upup (III) (III)
Volcano particles
100 µm core
Primary: 1000 coils 100 µm
Secondary: 1000 coils 100 µm
µµS GS G
Carlo Trigona A.A. 2007Carlo Trigona A.A. 2007--20082008
ResultsResults
WithWith magneticmagneticparticlesparticles
WithoutWithout magneticmagneticparticlesparticles
µµS GS G
Carlo Trigona A.A. 2007Carlo Trigona A.A. 2007--20082008
ExperimentalExperimental SetSet--upup (IV) (IV) µµS GS G
The experimental setThe experimental set--up consists of a RTDup consists of a RTD--Fluxgate magnetometer, operated Fluxgate magnetometer, operated with a sinusoidal bias signal @80Hz and 20 with a sinusoidal bias signal @80Hz and 20 mAppmApp of amplitude , a permanent of amplitude , a permanent magnet is used to polarize Etna volcanic ash (0.5 mm of diametermagnet is used to polarize Etna volcanic ash (0.5 mm of diameter--year of year of eruption 2001) contained in a plastic tube.eruption 2001) contained in a plastic tube.
FluxgateVolcanic ash
PermanentMagnet
Carlo Trigona A.A. 2007Carlo Trigona A.A. 2007--20082008
ResultsResults µµS GS G
The experiment has been conduced by observing the Fluxgate outpuThe experiment has been conduced by observing the Fluxgate output signal for t signal for different values of volcanic particle numbers. different values of volcanic particle numbers.
Carlo Trigona A.A. 2007Carlo Trigona A.A. 2007--20082008
ResultsResults µµS GS G
The next figure shows the evolution of the Residence Times DiffeThe next figure shows the evolution of the Residence Times Difference for rence for different volcanic ash quantities (from 0 ml to 3.5 ml) and thedifferent volcanic ash quantities (from 0 ml to 3.5 ml) and the RTD variation. RTD variation.
Variation of RTD as function of volcano Variation of RTD as function of volcano particles quantities particles quantities
Evolution of the Residence Times Evolution of the Residence Times Difference increasing the volcanic ash Difference increasing the volcanic ash
quantities.quantities.
Carlo Trigona A.A. 2007Carlo Trigona A.A. 2007--20082008
ConclusionsConclusions
RTRT--Fluxgate Fluxgate
PrinciplePrinciple
Expressions of RTD and SensitivityExpressions of RTD and Sensitivity
Fluxgate for biomedical applicationsFluxgate for biomedical applications
SetSet--up with PCB FR4up with PCB FR4
SetSet--up with “Wire” coreup with “Wire” core
Fluxgate for volcanic ash detectionFluxgate for volcanic ash detection
SetSet--up with PCB FR4up with PCB FR4
SetSet--up with “Wire” coreup with “Wire” core
µµS GS G
Carlo Trigona A.A. 2007Carlo Trigona A.A. 2007--20082008