[Uchiyama, Ushiba(remote)]

Summary:

We performed the swapping test of ETMX TM H1/H2 actuators and confirmed the problem is at the outside of the chamber.

Detail:

We performed the swapping test of ETMX TM H1/H2 actuators.
As usual, excitation was injected at 10Hz and we measured TF from excitation signals to TM OpLev PIT.
Figure 1 shows the results.

Left and right pannels show the results when H1 and H2 coil were actuated.
Blue and red represent the measurement before and after cable swapping.
Black line in the left pannels show the reference measured in 2024.

For H1 actuator, red line is higher than blue line by 3dB and comparable with black line, which means actuator efficiency was recovered by swapping the cable.
For H2 actuator, red line is lower than blue line by 3dB, which means actuator efficiency was removed by swapping the cable.
Therefore, we can conclude that the source of actuator efficiency reduction is not at the inside of chamber but at the outside.
Though we haven't confirmed which circuit has a problem, we don't have to reopen the chamber and check the suspension.