Magnettomographischer Versuchsaufbau

Applications based on tomographic methods solve inverse problems. The master-thesis covers the development of an experimental setup for magnetic tomography, based on the fact, that the magnetic tomography is also interpreted as an inverse problem. More precisely, an alternating magnetic field causes an induced voltage in sensing coils. Subsequently, these induced voltages give information on the local position of the source. To generate the alternating magnetic field, an electrolytic solution is supplied with alternating current. In the specific application, the electrolytic solution is contained in a tube made of acrylic glass. As the electrolyte, a sodium chloride-water solution is used. A consequence thereof is, that the electrical conductivity of sodium chloride-water-solutions is investigated in detail in this work. At the mechanical implementation of the experimental setup for magnetic tomography, a measuring apparatus is used, that includes 8 sensor coils and is placed around the electrolyte-column. Furthermore, a two dimensional movement of the measuring apparatus relative to the fixed electrolyte-column is realized by two motorized linear stages. Instrumentation and microphone amplifiers provide the necessary amplification of the induced voltage in the sensor coils. Via the analog inputs of a sound card, the sensor signals are finally captured, processed and analysed by a computer. The operation of the fully automated measurement on the experimental setup is provided by a graphical user interface (developed in Matlab). As shown by the final results, the positions of the coils detected by the tomographic based measurements are almost the same as the real positions, which are determined by the motorized linear stages. In conclusion it can be stated, that the requirements on the experimental setup for magnetic tomography are achieved very well. Keywords: tomography, inverse problem, electrolyte, alternating magnetic field, sensor coil