We injected a sinusoidal signal to each one of the four coils (DR, UR, DL, UL) of the NE and then WE payload. We used a 1Vrms at 15Hz set at the generator's output (but ~10% less applied to the coils due to a 9/10 partition for monitoring purpose).
Note that the Coils are used with the two wires shot-circuited, and the voltage sine is applied between these two wires and the Virgo ground (tower's vacuum chamber). When we apply the voltage to one coil the other three are connected.
The table below summarizes the measurements. The behaviour of both mirrors is consistent with that of a charged mirror. To be better investigated.
We noticed that when injecting at the WE, the noise floor in the region 20 to 40Hz sensibly decreased. See Figure 1. This also happens when leaving unplugged one coil.
Investigations to be continued. So we leave all the four WE coils unplugged for tests
GPS | Coil name | Freq (Hz) | Amplitude to Coil (Vrms) | DARM @ fundamental | DARM @ II Harmonic | NOTE |
1225622466 | quiet | |||||
1225622616 | NE, DR | 15 | 0.884 | 1E-5 | 1E-7 | |
1225622813 | NE, DR | 15 | x 0.5 | 0.5E-5 | 0.2E-7 | |
1225623242 | NE, UR | 15 | 0.871 | 7E-5 | 1E-7 | |
1225623559 | NE, DL | 15 | same | 7E-7 | 1E-7 | |
1225623811 | NE, UL | 15 | same | 4E-6 | 1E-7 | |
1225624030 | NE, DL | 15 | same | 8E-7 | 1E-7 | |
1225624151 | NE, DL | 15 | x 2 | 1.7E-6 | 4.5E-7 | |
1225624328 | NE, DL | 15 | x 4 | 3.5E-6 | 1.7e-6 | |
1225631639 | NE, DR | 15 | 0.877 | 1E-5 | 8E-8 | offset in cage position |
1225632568 | NE, UR | 15 | same | 2 E-5 | 7 E-8 | offset in cage position |
1225634751 | NE, UR | 15 | same | 2.4E-5 | 6.6E-8 | same |
1225634865 | NE, DL | 15 | same | 1E-8 | 7E-8 | same |
1225635095 | NE, UL | 15 | same | 1.7E-6 | 5.4E-8 | same |
1225635390 | NE, UR | 15 | same | 2E-5 | 7E-8 | same |
1225635718 | NE, UR | 27 | same | 2.4E-5 | 2.7E-8 | same |
1225637892 | quiet | |||||
1225639862 | WE, DR | 15 | same | 3E-6 | 7E-8 | |
1225640033 | WE, DL | 15 | same | 5.8E-5 | 7E-8 | |
1225640446 | WE, UR | 15 | same | 3E-5 | 7E-8 | |
1225640859 | WE, UL | 15 | same | 2.4E-5 | 7E-8 | |
1225640973 | WE | back to 4 coils connected | ||||
1225641075 | WE | DL floating | ||||
1225641183 | WE | short-circuit DL coil, floating --> UNLOCKS |