Figure 6

Custom designed mechanical assembly enabling the oscillation of a SPION sample inside the MPI bore. (a) CAD design, side view. (b) CAD design, top view. (c) Photography of manufactured assembly. The sample (6) is fixed on a slider (5) that is connected to a rotating plate (3) via a stiff rod. The rotating plate is driven by a DC motor (4), which is connected to a pulse-width modulation rotational speed controller. Calibration of “ground truth” sample velocity is performed by measuring the rotation frequency of the rotating plate. The rotation period is determined from the time difference between two consecutive light pulses (2) that are sensed by a photo detector (1).