Pronenko V. Development of methods of wideband induction magnetometers parameters improvement.

The thesis is dedicated to the problem of development of methods of wideband induction magnetometers (IM) improvement with the aim to increase the level of metrological and operational parameters with taking into account the specific requirements of modern application. The new version of equivalent circuit of wideband IM which contains differential link in the feed-back circuit by magnetic field and fully reflects its dynamic characteristics is proposed. The mathematical model of IM is constructed based on the proposed equivalent circuit. Stability and speed response analysis is done and method for the stability increment is proposed. It is demonstrated for the first time that the variation of parameters of the correction link in the feed-back circuit does not influence the speed of response of IM. The analysis of the IM main constructional parameters - core material and shape, numbers of the winding and others - influence on induction sensor transformation factor in wide frequency band and calculation of IM sensitivity threshold are made. The contribution of various sources in the total noise level of IM is analyzed. To reduce the sensitivity threshold when restrictions on the size are imposed the effectiveness of magnetic flux concentrators on the ends of the core is developed. The method of wide-band induction magnetometer parameters calculation is proposed which application allowed us to create a set of IM with improved level of parameters which are within best world specimens. A new method of IM quality estimation is proposed which allows comparison of different as to their construction IMs by the criterion of minimal level of the magnetic noise. All statements given in the work are experimentally verified and the correctness of the received recommendations and model relationships are proved.