[Ushiba]
Since the new magnet for IM/MN was deliverred, I measured actuator efficiency with new magnets.
Measurement was done by using scales and micrometer stages as usual.
However, during the measurement, I found that cans of PDs for photosensor has magnetism and MN magnets makes some force between them.
Attached fig1 and 2 shows the force when the current is off.
X-axis represents the position of the magnets surface measured from the coil surface (positive sign means the magnets enter the coil).
To see these graph, MN actuator makes some force even though no current was applied to the coil.
Attached fig 3 and 4 shows the force of Im actuator and MN actuator when I applied the current (100mA for IM and 10mA for MN).
Blue dots show the raw data and red dots show the subtruction of the background measured as fig 1 and 2.
From the result of fig 3 and 4, new actuator efficiency was calculated as 0.055N/A for IM and 1.1N/A for MN, which is 20% and 10% larger than my estimation but probably fine.
We need to consider how to treat the force between Mn magnets and cans of PDs.