Originally the 29.2Hz line seen in LSC_DARM was believed to be the A/C in the WE, however during the switch off of the A/C the line is still present (figure 1). Looking at the spectrogram of LSC_DARM we can also see the line is stable in amplitude and frequency. Bruco shows good coherence with WE accelerometers and seismometers. Looking at a FFT of the WE ENV sensors we can see (figure 2) the line is strongest in the Cryotrap Accelerometer, but the line can be seen in all WE ACC and SEIS. It is worth noting that the line is not present in the microphone. Just as a double check coherence was between DARM and all the sensors with the lines present (figure 3), as expected we see very good coherence.

Is there anything else we can switch off in the WE?