Today we did a seismic injection in the PR tower as well as an acoustic injection in the laser lab.
The seismic injection was made activating a small shaker that does not work below 10Hz. This was a coloured injection that started at 10:20a.m. and finished at 11:26a.m . We started with an amplitude of 1e-6, whose effect was not noticeable in the V1:ENV_B4_GHOST_ACC_Z channel. That is why we began to increase the amplitude of the injections progressively, until we reached 5e-3, which was noticeable in the aforementioned channel.
As for the acoustic injection, it was done thanks to a loudspeaker placed in the laser lab from 11:50a.m. to 12:20a.m. In order to analize its effect, we focused on V1:ENV_EIB_MIC, which is a microphone placed in the laser lab. Just as we had previously done with the shaker, we progressively increased the amplitude of the signal until we reached 2e-4. The loudspeaker does not work below 50 Hz, so we needed to change the band width with respect to that chosen for the seismic injections.
We must keep in mind that the sensitivity of the interferometer was very low below 100Hz, so all the effects regarding frequencies below 100Hz should not be seen as totally correlated to our injection.
It must be noticed that at 11:34a.m. we had to unplug the cable coming from the shaker and plug the one corresponding to the loudspeaker. It was at this moment that a bump and a reduction of the noise could be noticed.
Analysis will follow.