Magnetic injection map:
We performed a new set of near field magnetic injection to map the local couplings of the NI, WI, BS, SIB1, SDB1 towers
The plan was to do injections and terminals but we could not because the ITF repetedly unlocked due to a (new) mysterious noise occurring at the NEB
The attached file gives gps times and details.
25-min glitch investigation:
We perfomed the following actions
- unplugged the power supplier and pre-amplifier of the NI point absorber (TCS room)
- unplugged thepoint absorber pico-motors driver
- unplugged the thorlab module tri-axis piezo controller (piezo driver laser CO2)
- physically disconnected all the cables from the point absorber module (NI tower base)
- we left opended for the full shift duration (> 8 hours ) the door of the TCS rooom. Figure 1 shows the evolution of the temeprature of the TCS room and the PR CHRoCC parameter
Glitches are still there :-((
Any effect on the glitch rate has to be better checked
A new mysterious transient noise at NEB:
As described by Fabio in 63536, today starting from around 12:00 UTC the ITF unlocked several times because the NE suspension F0 got excited. A correlated noise is present in several ENV and NN sensors in NEB: accelerometers and microphones
From a preliminary analysis we notice that
- the noise is transient with a duration of a few seconds, the intensity of the noise is not always the same
- the noise has a peculiarr shape in the spectrogram, consisting of a peak excitation at few hundred of Hz followed by a "whisker": see Figure 2 and 3
- the noise source seems located inside the NEB experimental room, because looking at the NN microphonic array the mics placed inside the external technical rooms (number 6, 7 and 8) do not see the noise: Figure 4
- looking at the NN seismic array, the noise is not uniformely distributed inside the NEB hall, but is seems less intense at the far end of the room (towards the tunnel) and more intense along the west side of the room: Figure 5
- The rate of these glitches is not regular and not always caused an unlock: Figure 6 and Figure 7 (zoom)
- we also checked the NEB environmental dataset of the whole day, and it loooks that the noise first appeared around 11:45 UTC