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MAGNETOMETR Y Theoretical and experimental research. Baltag Octavian Ioan. Ligns of force of the geomagnetic field (Glatzmaier et Roberts, 1995). http://paleomag.uqar.ca/spip.php?article44. 1971 B.Sc. in Physics - specialized in Electroradiophysics "Alexandru Ioan Cuza" University of Iasi
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MAGNETOMETRY Theoretical and experimental research Baltag Octavian Ioan Ligns of force of the geomagnetic field (Glatzmaier et Roberts, 1995). http://paleomag.uqar.ca/spip.php?article44
1971 B.Sc. in Physics - specialized in Electroradiophysics "Alexandru Ioan Cuza" University of Iasi 1982 Ph.D. with a thesis entitled "Contributions to development of low magnetic fields magnetometers" Central Institute of Physics - Bucuresti
THEORETICAL AND APPLICATIVE RESARCH IN MAGNETOMETRY DIRECTIONS 1971 - 2001 MAGNETOMETRY Space applications Marine applications and naval degaussing Terrestrial – special applications Laboratory – research & industry MAGNETIC DETECTION Magnetic naval and terrestrial mines Industrial applications -buried metallic bodies METROLOGY, TRANSDUCERS & SPECIAL DEVICES PROTECTION OF INTELECTUAL & INDUSTRIAL PROPERTY Patents Trademarks ELECTROMAGNETIC COMPATIBILITY • Special applications • Research & industry
RESEARCH DOMAIN 2001 - 2008 HIGH RESOLUTION MAGNETOMETRY • Biomedical applications MICROWAVE RADIOMETRY • Microwave Thermografy – early detection of the breast cancer
Hex Hex Iex h U2f h + Hex h - Hex h h ferrofluid h Hex Iex U2f h I ex h Iex h U2f MAGNETOMETRY • Theoretical & experimental research on the fluxgate transducers for low magnetic field
B B +Bs H t -Bs d/dt H=H0sint h=0 h>0 t h>0 H U2f t Core I Core II t Fluxgate diagram
RESULTS AND APPLICATIONS • Research on the fluxgate transducers & magnetometer electronics –applications forIntercosmos 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
FLUXGATE WITH MULTIPLE PATH OF FLUXpatent RO, nr. 60.346, Int. Cl. G01R33/00 • Fluxgate sensor with multiple path of flux, O. Baltag, D. Costandache„ “Studies in applied electromagnetics and mechanics”, vol.13, pp.337-340, 1998, Editor: V. Kose, J. Sievert, IOS Press- Amsterdam, ISSN: 1383-7281 • Specifications: • Measuring range: +/- 200.000nT • noise: < 1 nT • excitation: pulse • liniarity: < 1% Core: permalloyprocessed by photogravure, trated in hidrogen, coil support: noriland cuartz powder
FLUXGATE WITH MULTIPLE PATH OF FLUXpatent RO, nr. 60.346, Int. Cl. G01R33/00
NONLINEAR RESONANCE PHENOMENA IN FLUXGATE Fluxgate 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.
Fluxgate – nonlinear resonance Transfer characteristic U2ω = f (h) of the fluxgate in second harmonic resonance regime U2f second harmonic amplitude H external magnetic field Uex excitation voltage f excitation frequency • 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
Nonlinear resonance - Applications • Double pumping magnetometer and measuring method, patent Ro, No. 67520, Int. Cl. G01R33/02 • Functional instability of ferromagnetic sensor in nonlinear resonance regime, digest, INTERMAG 96, Seattle, 1996 • Pecularities of the fluxgate responses in the parametric resonance regime, O. Baltag, D. Costandache, Sensors Letters, Vol. 7, No.3, pp. 276–277 (2009) Excitation frequency f=2000Hz: first pumping frequency External magnetic field frequency F=200Hz: second pumping frequency
DOUBLE PUMPING MAGNETOMETERPatent RO, no. 67520, Int. Cl. G01R33/02 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
FERROFLUID FLUXGATE TRANSDUCER • Behaviour of some nonlinear devices with ferrofluid, O. Baltag, D. Costandache, C. Cotae, JMMM, vol. 157 , pp. 591,1996 • Magnetometer with ferrofluid sensor, Baltag O., D.Costandache, IEEE Instrumentation & Measurement Technology Conference IMTC 96, Brussels, 1996, pp.263-265, ISBN: 0-7803-3312-8, IEEE Xplore, INSPEC Number: 5391810 • Sensor with ferrofluid for magnetic measurements, O. Baltag, D. Costandache, IEEE Trans. on Instrumentation and Measurement, vol. 46, nr.2, pp. 629-631, 1997 • Nonlinear behaviour of the ferrofluid in orthogonal magnetic fields, O. Baltag, D. Costandache, JMMM, 201, pp.123-125, 1999 • The study of a magnetic fluid based sensor, C. Cotae, O. Baltag, R.Olaru, D.Calarasu, D.Costandache, JMMM, 201, pp.393-397, 1999 • Sensor with ferrofluid for magnetic measurements, O. Baltag, D. Costandache, Conference on Precision Electromagnetic Measurements, Braunschweigh, June 1996, CPEM-96, pp.61-62, ISBN: 0-7803-3376-4
FERRITE FLUXGATE • Gaussmeter, O.Baltag, D. Costandache, IEEE Proceedings of the International Symposium on Signal, Circuits & Systems, Iasi 1995, pp. 473 • Magnetic field measurement with soft ferrite cored sensors, Baltag O., D. Costandache, 7-th, International Conference on Ferrites, Bordeaux,1996 • Toroidal Fluxgate Sensor Compared in Dynamic Preisach Framework, Salceanu A., Baltag O., Costandache D., The 7-th European Magnetic Materials and Applications Conference, EMMA ‚98, Zaragoza, Spain, pp. 248
AMORPHOUS AND NANOCHRISTALINE FLUXGATE • Preisach approach for modelling an amorphous toroidal fluxgate sensor, A. Salceanu, O. Baltag, D.Costandache, Sensor and Actuators, A, vol. 81, pp.207-211, 1999, ISSN: 0925-4005 • Study of a magnetic field sensor with nanocrystalline materials, Salceanu A., Baltag O., et all, Bul.Inst.Politehnic Iaşi, Tom XLV (IL), Fasc.5A, pp.381-384, 1999, ISSN 0258-9109 • Fluxgate sensor with nanocrystaline ferromagnetic core, Baltag O., M.Craus, D. Costandache, "43 Internationales Wissenschaftliches Kolloquium", Ilmenau , sept. 1998 • Study of a ferrite sensor for medium magnetic field intensity measurement, O. Baltag, D. Costandache, A. Salceanu, Studies in applied electromagnetics and mechanics, in „Studies in Applied Electromagnetics and Mechanics”, vol.18, Editori: P.di Barba, A. Savini, pp.665-669, 2000, IOS Press-Amsterdam, ISSN: 1383-7281
ELECTRONIC CIRCUITS FOR FLUXGATE MAGNETOMETER Electronic devices for fluxgate excitation and generating of reference signal,Patent RO., No. 80140 (1982), Int. Cl. G01G33/02
Reference 2f Negative feedback circuit Us D.C. Amplifier h Ue Excitation Generator S Excitation generator Ur = Ue Selective amplifier Phase shift Synchro-nous Detector ir Ur hr Fluxgate f Feedback coil Ku , Ki , rr Frequency divider 1/2 Generator 2f Reference 2f ELECTRONIC CIRCUITS FOR FLUXGATE MAGNETOMETER • Negative feedback network
ELECTRONIC CIRCUITS FOR FLUXGATE MAGNETOMETER Integrated hybrids circuits for magnetometry - ceramics support - resistors – laser trimming - active components: integrated circuits - packaging – epoxy resins and quartz powder