11

MAGNETOMETRYTheoretical and

experimental research

Baltag Octavian IoanBaltag Octavian Ioan

Ligns of force of the geomagnetic field (Glatzmaier et Roberts, 1995). http://paleomag.uqar.ca/spip.php?article44

22

1971 B.Sc. in Physics - specialized in 1971 B.Sc. in Physics - specialized in Electroradiophysics "Alexandru Ioan Cuza" Electroradiophysics "Alexandru Ioan Cuza" University of IasiUniversity of Iasi

1982 Ph.D. with a thesis entitled 1982 Ph.D. with a thesis entitled "Contributions to development of low "Contributions to development of low magnetic fields magnetometers"magnetic fields magnetometers" Central Institute of Physics - BucurestiCentral Institute of Physics - Bucuresti

33

THEORETICAL AND APPLICATIVE THEORETICAL AND APPLICATIVE RESARCH IN MAGNETOMETRY RESARCH IN MAGNETOMETRY

DIRECTIONS 1971 - 2001DIRECTIONS 1971 - 2001

MAGNETOMETRYMAGNETOMETRY Space applicationsSpace applications Marine applications and naval Marine applications and naval

degaussing degaussing Terrestrial – special applicationsTerrestrial – special applications Laboratory – research & industryLaboratory – research & industry

MAGNETIC DETECTIONMAGNETIC DETECTION Magnetic naval and Magnetic naval and

terrestrial mines terrestrial mines Industrial applications -Industrial applications -

buried metallic bodiesburied metallic bodies

METROLOGMETROLOGYY,,

TRANSDUCERS & SPECIAL TRANSDUCERS & SPECIAL DEVICESDEVICES

PROTECTION OF INTELECTUAL & INDUSTRIAL PROPERTYPROTECTION OF INTELECTUAL & INDUSTRIAL PROPERTY Patents Patents TrademarksTrademarks

ELECTROMAGNETIC ELECTROMAGNETIC COMPATIBILITYCOMPATIBILITY

Special applicationsSpecial applications Research & industryResearch & industry

44

HIGH RESOLUTION MAGNETOMETRYHIGH RESOLUTION MAGNETOMETRY BBiomedical iomedical applicationsapplications

MICROWAVE MICROWAVE RADIOMETRRADIOMETRYY Microwave Microwave TThhermografermografy y – – early early detectidetection of the on of the

breast cancerbreast cancer

RESEARCH DOMAIN 2001 - 2008RESEARCH DOMAIN 2001 - 2008

55

MAGNETOMETRYMAGNETOMETRY

Theoretical & experimental research on the fluxgate transducers for Theoretical & experimental research on the fluxgate transducers for low magnetic fieldlow magnetic field

U2fh

I ex

h h

H

ex

H

ex

h + Hex

h - Hex

h

Hex

U2f

Iex

h

h U2f

Iex

Iex

h

ferrofluid

66

Fluxgate diagramFluxgate diagram

B

H

B

t

+Bs

-Bs

d/dt

t

h>0h=0

t

H=H0sint

h>0

Core I

Core II

tU2f

H

77

RESULTS AND APPLICATIONSRESULTS AND APPLICATIONS

Research on the fluxgate Research on the fluxgate transducers & transducers & magnetometmagnetometer er electronics –electronics – applications forapplications for Intercosmos satellitesIntercosmos satellites

Technical data:• range: +/- 80.000 nT• frequency of pulse excitation: 2 kHz,• second harmonic: 4 kHz• noise: < 1 nT• nonlinearity : < 1%• applications: triaxial magnetometer for Intercosmos satellites

88

FLUXGATE WITH MULTIPLE PATH OF FLUXFLUXGATE WITH MULTIPLE PATH OF FLUXpatent RO, nr. 60.346, Int. Cl. G01R33/00patent RO, nr. 60.346, Int. Cl. G01R33/00

Fluxgate sensor with multiple path Fluxgate sensor with multiple path of fluxof flux, O. Baltag, D. , O. Baltag, D. Costandache„Costandache„ “ “Studies in applied Studies in applied electromagnetics and mechanics”, electromagnetics and mechanics”, vol.13, pp.337-340, 1998, Editor: V. vol.13, pp.337-340, 1998, Editor: V. Kose, J. Sievert, IOS Press- Kose, J. Sievert, IOS Press- Amsterdam, ISSN: 1383-7281Amsterdam, ISSN: 1383-7281

Specifications:• Measuring range: +/- 200.000nT• noise: < 1 nT• excitation: pulse • liniarity: < 1%

Core: permalloy processed by photogravure, trated in hidrogen, coil support: noril and cuartz powder

99

FLUXGATE WITH MULTIPLE PATH OF FLUXFLUXGATE WITH MULTIPLE PATH OF FLUX patent RO, nr. 60.346, Int. Cl. G01R33/00patent RO, nr. 60.346, Int. Cl. G01R33/00

1010

NONLINEAR RESONANCE PHENOMENA IN NONLINEAR RESONANCE PHENOMENA IN FLUXGATEFLUXGATE

Fluxgate transfer characteristic in nonlinear resonance regimeFluxgate transfer characteristic in nonlinear resonance regime

Specific phenomena:• In certain operation conditions the fluxgate transducer no longer works as a magnetic field sensor and it is generating an almost quasisinusoidal signal with a frequency equal to the odd or even harmonics of the excitation signal• The second harmonic phase can only be changed (with 180°) by applying a continuous or alternative magnetic field exceeding the threshold value characteristic to the regime.

1111

Fluxgate – nonlinear resonance

Transfer characteristic U2ω = f (h) of the fluxgate in second harmonic resonance regime

Hysteresis response to applied field of the fluxgate on second harmonic:

- UQ second harmonic quadrature component- US second harmonic, sinphasic component- UA second harmonic amplitude- H external magnetic field

U2f second harmonic amplitude

H external magnetic fieldUex excitation voltagef excitation frequency

1212

Nonlinear resonance - ApplicationsNonlinear resonance - Applications

Double pumping magnetometer and Double pumping magnetometer and measuring methodmeasuring method,, patent Ro, No. patent Ro, No. 67520, Int. Cl. 67520, Int. Cl. G01R33/02G01R33/02

Functional instability of ferromagnetic Functional instability of ferromagnetic sensor in nonlinear resonance regimesensor in nonlinear resonance regime, , digest, digest, IINTERMAG 96,NTERMAG 96, Seattle, 1996 Seattle, 1996

Pecularities of the fluxgate responses Pecularities of the fluxgate responses in the parametric resonance regime, in the parametric resonance regime, O. O. Baltag, D. Costandache, Baltag, D. Costandache, Sensors Sensors Letters, Vol. 7, No.3, pp. 276–277 (2009Letters, Vol. 7, No.3, pp. 276–277 (2009))

Excitation frequency f=2000Hz: first pumping frequency

External magnetic field frequency F=200Hz: second pumping frequency

1313

DOUBLE PUMPING MAGNETOMETERDOUBLE PUMPING MAGNETOMETERPatent RO, no. 67520, Int. Cl. Patent RO, no. 67520, Int. Cl. G01R33/02G01R33/02

Fluxgate responses U2f (second harmonic 2f) at second pumping field F=200Hz, and measuring field Ho

Second harmonic U2f of the fluxgate modulated in amplitude by second pumping field with frequency F=200Hz

Functional characteristics:• first pumping frequency (fluxgate excitation): f=2 kHz• second pumping frequency: F=200 Hz• noise: < 0,1 nT• measuring range: +/- 200.000 nT

1414

FERROFLUID FLUXGATE TRANSFERROFLUID FLUXGATE TRANSDDUCERUCER

Behaviour of some nonlinear devices with ferrofluid, O. Baltag, D. Costandache, Behaviour of some nonlinear devices with ferrofluid, O. Baltag, D. Costandache, C. Cotae, JMMM, vol. 157 , pp. 591,1996C. Cotae, JMMM, vol. 157 , pp. 591,1996

Magnetometer with ferrofluid sensor, Baltag O., D.Costandache, IEEE Magnetometer with ferrofluid sensor, Baltag O., D.Costandache, IEEE Instrumentation & Measurement Technology Conference IMTC 96, Brussels, Instrumentation & Measurement Technology Conference IMTC 96, Brussels, 1996, pp.263-265, ISBN: 0-7803-3312-8, IEEE Xplore, INSPEC Number: 1996, pp.263-265, ISBN: 0-7803-3312-8, IEEE Xplore, INSPEC Number: 53918105391810

Sensor with ferrofluid for magnetic measurements, O. Baltag, D. Costandache, Sensor with ferrofluid for magnetic measurements, O. Baltag, D. Costandache, IEEE Trans. on Instrumentation and Measurement, vol. 46, nr.2, pp. 629-631, IEEE Trans. on Instrumentation and Measurement, vol. 46, nr.2, pp. 629-631, 19971997

Nonlinear behaviour of the ferrofluid in orthogonal magnetic fields, O. Baltag, D. Nonlinear behaviour of the ferrofluid in orthogonal magnetic fields, O. Baltag, D. Costandache, JMMM, 201, pp.123-125, 1999Costandache, JMMM, 201, pp.123-125, 1999

The study of a magnetic fluid based sensor, C. Cotae, O. Baltag, R.Olaru, The study of a magnetic fluid based sensor, C. Cotae, O. Baltag, R.Olaru, D.Calarasu, D.Costandache, JMMM, 201, pp.393-397, 1999D.Calarasu, D.Costandache, JMMM, 201, pp.393-397, 1999

Sensor with ferrofluid for magnetic measurements, Sensor with ferrofluid for magnetic measurements, O. Baltag,O. Baltag, D. Costandache, D. Costandache, Conference on Precision Electromagnetic Measurements, Braunschweigh, June Conference on Precision Electromagnetic Measurements, Braunschweigh, June 1996, CPEM-96, pp.61-62, ISBN: 0-7803-3376-41996, CPEM-96, pp.61-62, ISBN: 0-7803-3376-4

1515

FERRITE FLUXGATEFERRITE FLUXGATE

GGaussmeter, O.Baltag, D. Costandache, IEEE Proceedings of the aussmeter, O.Baltag, D. Costandache, IEEE Proceedings of the International Symposium on Signal, Circuits & Systems, Iasi 1995, pp. 473International Symposium on Signal, Circuits & Systems, Iasi 1995, pp. 473

Magnetic field measurement with soft ferrite cored sensors, Baltag O., D. Magnetic field measurement with soft ferrite cored sensors, Baltag O., D. Costandache, 7-th, International Conference on Ferrites, Bordeaux,1996Costandache, 7-th, International Conference on Ferrites, Bordeaux,1996

Toroidal Fluxgate Sensor Compared in Dynamic Preisach Framework, Toroidal Fluxgate Sensor Compared in Dynamic Preisach Framework, Salceanu A., Baltag O., Costandache D., The 7-th European Magnetic Salceanu A., Baltag O., Costandache D., The 7-th European Magnetic Materials and Applications Conference, EMMA ‚98, Zaragoza, Spain, pp. 248Materials and Applications Conference, EMMA ‚98, Zaragoza, Spain, pp. 248

1616

AMORPHOUS AND NANOCHRISTALINE AMORPHOUS AND NANOCHRISTALINE FLUXGATEFLUXGATE

Preisach approach for modelling an Preisach approach for modelling an amorphous toroidal fluxgate sensor, A. amorphous toroidal fluxgate sensor, A. Salceanu, O. Baltag, D.Costandache, Salceanu, O. Baltag, D.Costandache, Sensor and Actuators, A, vol. 81, pp.207-211, Sensor and Actuators, A, vol. 81, pp.207-211, 1999, ISSN: 0925-40051999, ISSN: 0925-4005

Study of a magnetic field sensor with Study of a magnetic field sensor with nanocrystalline materials, Snanocrystalline materials, Saalceanu A., Baltag lceanu A., Baltag O., et all, Bul.Inst.Politehnic Iaşi, Tom XLV (IL), O., et all, Bul.Inst.Politehnic Iaşi, Tom XLV (IL), Fasc.5A, pp.381-384, 1999, ISSN 0258-9109Fasc.5A, pp.381-384, 1999, ISSN 0258-9109

Fluxgate sensor with nanocrystaline Fluxgate sensor with nanocrystaline ferromagnetic core, Baltag O.ferromagnetic core, Baltag O.,, M.Craus, D. M.Craus, D. Costandache, "43 Internationales Costandache, "43 Internationales Wissenschaftliches Kolloquium", Ilmenau , Wissenschaftliches Kolloquium", Ilmenau , sept. 1998sept. 1998

Study of a ferrite sensor for medium magnetic Study of a ferrite sensor for medium magnetic field intensity measurement, O. Baltag, D. field intensity measurement, O. Baltag, D. Costandache, A. Salceanu, Studies in applied Costandache, A. Salceanu, Studies in applied electromagnetics and mechanics, in „Studies in electromagnetics and mechanics, in „Studies in Applied Electromagnetics and Mechanics”, Applied Electromagnetics and Mechanics”, vol.18, Editori: P.di Barba, A. Savini, pp.665-vol.18, Editori: P.di Barba, A. Savini, pp.665-669, 2000, IOS Press-Amsterdam, ISSN: 669, 2000, IOS Press-Amsterdam, ISSN: 1383-72811383-7281

1717

ELECTRONIC CIRCUITS ELECTRONIC CIRCUITS FOR FLUXGATE MAGNETOMETERFOR FLUXGATE MAGNETOMETER

Electronic devices for fluxgate Electronic devices for fluxgate excitation and generating of excitation and generating of reference signalreference signal,, Patent RO., No. Patent RO., No. 8014080140 ( (19821982), Int. Cl. ), Int. Cl. G01G33/02G01G33/02

1818

ELECTRONIC CIRCUITS ELECTRONIC CIRCUITS FOR FLUXGATE MAGNETOMETERFOR FLUXGATE MAGNETOMETER

Negative feedback networkNegative feedback network

Fluxgate

Reference 2fFrequency divider 1/2

Synchro-nous

Detector

Phase shift

Selective amplifier

Excitationgenerator

Generator2f

f

D.C. AmplifierNegative feedback

circuit

ExcitationGenerator

SUe

h

hr

ir

Ur

Feedbackcoil

Ku , Ki , rr

Ur = Ue

Us

Reference 2f

1919

ELECTRONIC CIRCUITS ELECTRONIC CIRCUITS FOR FLUXGATE MAGNETOMETERFOR FLUXGATE MAGNETOMETER

Integrated hybrids circuits for Integrated hybrids circuits for magnetometrymagnetometry

- ceramics support - ceramics support

- resistors – laser trimming- resistors – laser trimming

- active components: integrated - active components: integrated circuits circuits

- packaging – epoxy resins and - packaging – epoxy resins and quartz powderquartz powder