Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

Magnetic Particle Tracking is able to track the position and orientation of magnetic particles in opaque media by measuring the magnetic field outside the vessel. This technique was already applied in granular flows with a magnet of 8 mm³ volume [1]. The extension of this technique to flotation, which is used in ore processing and recycling, requires magnetic particles in sub-mm range, which float with the foam. The vessel diameter of 100 mm demands for sensors with a resolution in the order of nT. Thin-film sensors reduce the distance from the sensor to the magnet. We will present in detail a newly developed measurement system with an array of 12 tailored planar Hall magnetoresistive sensors with a measurement range from 300 µT down to 10 nT and
demonstrate the reliable detection of the position of a cubic magnet with edge length of 0.4 mm. The sensors consist of single layer permalloy in a 5 ring Wheatstone bridge configuration. Furthermore, we will show preliminary results of an sensor array on a flexible substrate [2],
which can be easily and accurately placed around a complex shaped vessel.
[1] Buist, et al. AIChE Journal 60.9 (2014): 3133-3142.
[2] Granell, et al. npj Flexible Electronics 3.1 (2019): 3.