Application Of Magnetometers Research Articles

SQUID magnetometer noise measurements on YBa/sub 2/Cu/sub 3/O/sub 7/ thin films and input coils

A SQUID magnetometer system incorporating a NB-based conventional SQUID operating at 4.8 K was used to measure the magnetic field noise from high-T/sub c/ input coils and unpatterned films at 77 K. The system allows for the rapid measurement of relatively large regions of high-T/sub c/ material. The results on numerous coils and films show the noise decreasing as a function of increasing film critical current density at 77 K. High-T/sub c/ films with J/sub c/(77 K)=3*10/sup 6/ A/cm/sup 2/ appear suitable for use as input coils in SQUID magnetometer applications requiring low noise at frequencies down to 1 Hz.

Some remarks on the history of Wingst Geomagnetic Observatory during the first 50 years

For the reason of the 50th anniversary of the Wingst Geomagnetic Observatory of the Deutsches Hydrographisches Institut celebrated on the 30th April 1988, the development of this Observatory and its activities on the background of the social and scientific occurrences during the last 50 years are presented. Contributions of the Observatory to theKp index, the research about the North German conductivity anomaly, geomagnetic measurements at sea, and the application of proton magnetometers as well as other geomagnetic instruments are described.

Observation of tongue movements employing magnetometer sensor

This paper introduces a new application of magnetometers employing the magnetic core to monitoring the motion of the tongue in speech. The monitoring system consists of two magnetometers and a small permanent magnetic rod which is fixed on the tongue surface. The basic principle for measuring makes use of the output changes induced in the magnetometers due to the changes of the distance between the magnetometers and the rod which moves together with the tongue. Repeated experiments have led us to the conclusion that this magnetic method is a powerful technique for speech physiology research because of its simplicity, safety, economy, and flexibility for signal presentation.

Advances in optically pumped He4 magnetometers : Resonance and nonresonance techniques

Samples of optically pumped 23S1 helium atoms are currently studied in our laboratory for use in advanced magnetometer applications. The results of recent investigations of the effect of pumping beam orientation with respect to the observed magnetic field are presented in this paper. The orientation dependence of the amplitude and frequency of the magnetic resonance signal observed by optical techniques has been measured. These results are used to predict the effect of orientation on scalar field change measurements. The experiments are theoretically interpreted by taking into account the contribution of the individual magnetic resonances and the perturbation of magnetic states by real and virtual transitions. The orientation dependence of the optical pumping process is used to construct a nonresonance magnetometer (no magnetic resonance) suitable for measuring vector interplanetary and laboratory fields in the range — 200 γ ≤ H ≤ 200 γ. Several new optical pumping components which have contribued to the advancement of helium magnetometers are discussed.