[Irene, Camilla, Federico]

 

Some conclusion drawn from data taken with a trillium seismomenter placed on TAMA floor (behind squeezing clean room, below mode cleaner pipe).

 

1) Figures 1, 2, 3 show spectrograms (GPS is in UTC). Only for the day 21/11 we have 24h of data.

 

2) Noise between 1-30 Hz changes between day and night. Figure 4 highlights it.

 

3) There is a device that turns off/off every ~ 8 minutes, which produces the peaks at 24.5 Hz (fan? air conditioning? pump?). See plot 5.

 

4) Figure 6 shows the percentiles calculated on a day. Some other non-stationary peaks, in addition to that at 24.5 Hz, are clearly visible

 

5) Comparing trillium spectrum with the TEAC seismometer we have in TAMA it seems the TEAC is useful only between 10Hz and 50 Hz. Its own noise dominates below 10Hz, while ADC noise dominates above 50Hz (To Be Confirmed) - Plot to be posted.

 

 

Good face to face!Figures 1, 2, 3 are spectrograms (GPS is in UTC). Only for the

November 21 we have 24h of data.

 

1) you see the peak around 10 Hz that you told us about. In reality

it is very wide, between 1-30 Hz, and from the spectrograms we see that it "breathes"

between day and night. Figure 4 highlights it, they are two spectra:

one by day, the other by night.

 

2) There is a device that turns off / on every 8 minutes or so, which makes the

peaks at 24.5 Hz (one fan? air conditioning? pump?). See plot 5.

 

3) Figure 6 is the percentiles calculated on a day. They look good

some non-stationary peaks, beyond that at 24.5 Hz.

 

That's all. We have no more precise conclusions, it should be understood

which are the devices that generate the peaks, but we have had no way

to analyze the data in time to do so. :)

 

Good face to face!