Using the prepared setup we injected a sweep of lines between 1kHz and 30Hz.The qualitative impression is that the impact of DARM is small.

Figure 1 shows the injection sweep. Figure 2 zooms in the region between  1kHz and 450Hz were some noise excess in DARM is measured. No sensible effect is produced below 200Hz, althogh the injected vibration of DT tower as measured by the accelerometer on the W flange itself (ENV_DT_FLANGE_W_ACC_Z) and on the opposite side (ENV_DT_ACC_Z) at each frequency was at least  ten times the quiet level.

We checked a few frequencies around 360Hz, 408Hz, 432Hz and 461Hz which are very close to the where in quiet conditions  DARM and DT accelerometers are coherent: Figures 4, 5, 6 and 7. Here indeed the DARM excitation is well visible. No excitation is seen in MICH.

Data have to be analized to quantify the coupling.

Attached is the log file with injection times. A reference quiet time is: 1181896100, for 300s

Here is are the injection parameters used:

ctrl17[~/irene/injections/scripts]: ENV_swept_sine_cured.py

DAC channel (i.e. NOISE_CEB_DAQroom, EEroom, DetEER, NOISE_WEB,NEB): NOISE_CEB_DetEEroom
Log file name (to be read by Matlab code): DT_flangeW_20170619.txt
Start frequency (Hz): 10
Stop frequency (Hz): 1000
Number of points (integer): 150
Number of averages (integer): 4
Number of cycles (integer): 10
Minimum average time (float, seconds): 8

Please enter measurement amplitude envelope in freq/amp pairs (a single amplitude is accepted)
For example (3 envelope points): 1 5e-1 10 5e-2 100 2e-2
Measurement amplitude envelope in freq/amp pairs: 0.5