We developed a system to detect the magnetic nanoparticles utilizing AC susceptibility measurement. In this system, room temperature pickup coil made of copper wire was used as a sensor to detect the magnetic signal from the particles. In this method, an AC excitation field was applied to the particles, and the resulting signal field from the particles was detected with pickup coil. We used the differential double pickup coils with special configuration in order to reduce the coupling of the excitation field to the pickup coil and to suppress an additional magnetic noise from a substrate. With this configuration, the coupling of the excitation field to the pickup coil can be reduced to less than 1/10 6, and the additional noise from substrate can be also eliminated. We also increased the number of turns of pickup coil and used the sample with high magnetic susceptibility in order to enhance the detectable field signal from particles. As a result, the minimum detectable weight of particles reaches to 1 ng. With experimental result and simulation, we calculated the magnetic susceptibility of particles in applied excitation field.
|Number of pages
|Research Reports on Information Science and Electrical Engineering of Kyushu University
|Published - Sept 2004
All Science Journal Classification (ASJC) codes
- General Computer Science
- Electrical and Electronic Engineering