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Environmental Monitoring (Environmental Monitoring)
fiori - 18:21 Friday 26 April 2019 (45751) Print this report
Low frequency acoustic injections CEB

(BNS range oscillating between 44 and 41 Mpc .... not the optimal condition for injections)

We inject a set of low frequency acoustic lines in CEB hall using the two subwoofers setup. Injected frequencies 115, 95, 85, 73, 65, 54, 45, 40, 32, 27, 23, 19, 14, 43, 58.6Hz

(noticeably the subwoofer manages to inject quite loud lines down to 14Hz!)

We are able to inject acoustic lines at least a factor 10 above hall background noise. Not negligible noise leaks in DET LAB: microphone on SQZ bench measures a line that is a factor 5 to just 2 less than as measured in the hall.

We do not see effects in DARM or Hrec. Figura 1 = spectrogram of injected lines. An upper limit projection will follow.

We then tried some COLORED noise, in the band from 10Hz to 100Hz or so. In this case we do see some effect in DARM between 40 and 80Hz. Roughly we see a factor 3 increase of noise in DARM when HALL noise is more than a factor 20 above background and SQZ bench microphone noise is a factor 10 above background. See Figure 2. and 3. An upper limit projection will follow,

We tried to reproduce the noise increase injecting a line at 58.6Hz with an amplitude that is about a factor 100 larger than bkg in the hall mic, some effect is seen in DARM, but much smaller than with the broadband injection: Figura 4.

Conclusions: Acoustic noise increase of a factor up to 10 in the hall seems not to affect DARM significantly. DARM is sensitive to broadband acoustic noise in the 40 to 80Hz range exceeding a factor 20 in the hall. This noise could be passing through DETection LAB. This suspect is linked to the noise reduction effect that we measured last friday when switching off DET lab air conditioner (45588).

Here below the detailed log file with injection times:

quietREF: 1240303187  26 Apr 2019 08:39:29 UTC  (26 Apr 2019 10:39:29 CEST)

%------ start injecting LINES (fft 4s) ---------
115Hz, 1e-4: 1240303689  26 Apr 2019 08:47:51 UTC  (26 Apr 2019 10:47:51 CEST)
115Hz, 1e-3: 1240303781  26 Apr 2019 08:49:23 UTC  (26 Apr 2019 10:49:23 CEST): ok si vede nei microfoni HALL e SQZ (10 volte meno)
95Hz, 5e-3: 1240304222  26 Apr 2019 08:56:44 UTC  (26 Apr 2019 10:56:44 CEST): ok, almeno 10 volte sopra fondo, niente in hrec (8e-3 hall, 1e-3 sqz)
95Hz, 5e-3: 1240304468  26 Apr 2019 09:00:50 UTC  (26 Apr 2019 11:00:50 CEST): (3e-3 hall, 1e-3 sqz, niente hrec)
85Hz, 8e-3: 1240304658  26 Apr 2019 09:04:00 UTC  (26 Apr 2019 11:04:00 CEST): (5e-3 hall, 1.5 e-3 sqz, niente darm)
73Hz, 1e-2: 1240304814  26 Apr 2019 09:06:36 UTC  (26 Apr 2019 11:06:36 CEST): (5e-3 hall, 2e-3 sqz, niente darm)
73Hz, 1.5e-2: 1240305007  26 Apr 2019 09:09:49 UTC  (26 Apr 2019 11:09:49 CEST): (8e-3 hall, 4e-3 sqz, niente darm)
64Hz, 2.5e-2: 1240305301  26 Apr 2019 09:14:43 UTC  (26 Apr 2019 11:14:43 CEST): (1.5e-3 hall, 2e-3 sqz, niente darm)
65Hz, 2.5e-2: 1240305371  26 Apr 2019 09:15:53 UTC  (26 Apr 2019 11:15:53 CEST): (1.5e-3 hall, 1.5e-3 sqz, niente darm)
54Hz, 2.5E-2: 1240305525  26 Apr 2019 09:18:27 UTC  (26 Apr 2019 11:18:27 CEST): 5e-2 hall, 5e-3 sqz, nothing DARM
45Hz, 2.5e-2: 1240305718  26 Apr 2019 09:21:40 UTC  (26 Apr 2019 11:21:40 CEST): 1.5e-2 hall, 2e-3 SQZ, bozzetto in DARM?
off: 1240305915  26 Apr 2019 09:24:57 UTC  (26 Apr 2019 11:24:57 CEST): ok sembra sparito... in DARM
45Hz, 2.5E-2: 1240306018  26 Apr 2019 09:26:40 UTC  (26 Apr 2019 11:26:40 CEST): non si vede nulla in DARM
45Hz, 5e-2: 1240306152  26 Apr 2019 09:28:54 UTC  (26 Apr 2019 11:28:54 CEST): nothing DARM
40Hz, 3E-2: 1240306268  26 Apr 2019 09:30:50 UTC  (26 Apr 2019 11:30:50 CEST)
40Hz, 5e-2: 1240306367  26 Apr 2019 09:32:29 UTC  (26 Apr 2019 11:32:29 CEST): 1e-2 hall, 8e-2 sqz, niente darm
32Hz, 5e-2: 1240306502  26 Apr 2019 09:34:44 UTC  (26 Apr 2019 11:34:44 CEST): 1.5e-2 hall, 3e-3 sqz, no darm
27Hz, 5e-2: 1240306800  26 Apr 2019 09:39:42 UTC  (26 Apr 2019 11:39:42 CEST): 1e-2 hall, 3e-3 sQZ, no darm
23Hz, 5e-2: 1240306970  26 Apr 2019 09:42:32 UTC  (26 Apr 2019 11:42:32 CEST): 2e-3 hall, 8e-3 SQZ
23Hz, 0.1: 1240307160  26 Apr 2019 09:45:42 UTC  (26 Apr 2019 11:45:42 CEST): 5e-3 hall, 1.2e-2 SQZ (penso si sta trasmettendo via strutturale in DET LAB) no DARM
19Hz, 0.15: 1240307321  26 Apr 2019 09:48:23 UTC  (26 Apr 2019 11:48:23 CEST): 1.5e-2 hall, 1e-2 SQZ
19Hz, 0.2: 1240307447  26 Apr 2019 09:50:29 UTC  (26 Apr 2019 11:50:29 CEST): 2e-2 hall, 1.2e-2 SQZ, no DARM
15Hz, 0.2: 1240307602  26 Apr 2019 09:53:04 UTC  (26 Apr 2019 11:53:04 CEST): 3e-2 hall, quasi invisible in SQZ (paragonabile a rumore fondo, circa 2e-2), leggero peggioramento DARM?
OFF: 1240307602  26 Apr 2019 09:53:04 UTC  (26 Apr 2019 11:53:04 CEST), ripeto (in DARM 15Hz si sovrappone a linee calib)
14Hz, 0.3: 1240307902  26 Apr 2019 09:58:04 UTC  (26 Apr 2019 11:58:04 CEST): 3e-2 hall, invisible in SQZ paragonabile a rumore fondo, circa 3e-2, leggero effetto in DARM?
OFF: 1240308075  26 Apr 2019 10:00:57 UTC  (26 Apr 2019 12:00:57 CEST), nessun effetto in DARM, sembra normale fluttuazione.
45Hz, 0.03: 1240308300  26 Apr 2019 10:04:42 UTC  (26 Apr 2019 12:04:42 CEST): 2e-2 hall, 3e-3 sqz, no darm
43Hz, 0.03: 1240308455  26 Apr 2019 10:07:17 UTC  (26 Apr 2019 12:07:17 CEST): 2e-2 hall, 3e-3 sqz, no darm
OFF: 1240308842  26 Apr 2019 10:13:44 UTC  (26 Apr 2019 12:13:44 CEST)

%---------- COLORED noise
white 5e-4, 60, 100: 1240309116  26 Apr 2019 10:18:18 UTC  (26 Apr 2019 12:18:18 CEST)
white 5e-3, 50, 80: 1240309321  26 Apr 2019 10:21:43 UTC  (26 Apr 2019 12:21:43 CEST)
white 1e-2, 40, 60: 1240309436  26 Apr 2019 10:23:38 UTC  (26 Apr 2019 12:23:38 CEST): sembra piccolo impatto in darm: tra 40 e 70Hz
white 3e-2, 30, 40:  1240309633  26 Apr 2019 10:26:55 UTC  (26 Apr 2019 12:26:55 CEST): effetto well visible in DARM, struttura piu' eccitata: 58Hz, 45Hz
OFF: 1240309849  26 Apr 2019 10:30:31 UTC  (26 Apr 2019 12:30:31 CEST)

58.6Hz, 0.03: 1240309982  26 Apr 2019 10:32:44 UTC  (26 Apr 2019 12:32:44 CEST): quasi 0.1 hall, 3e-3 sqz, piccolo effetto in DARm
58.4 0.03: 1240310126  26 Apr 2019 10:35:08 UTC  (26 Apr 2019 12:35:08 CEST): niente in DARM
OFF: 1240310212  26 Apr 2019 10:36:34 UTC  (26 Apr 2019 12:36:34 CEST)

 

 

 

Images attached to this report
Comments to this report:
fiori - 18:54 Sunday 28 April 2019 (45761) Print this report

Here some attempted projections of the data of subwoofer injections.

  • Figure 1: is the projection of HALL acoustic noise (that is using the Hall microphone) to Hrec using the injected lines. In this case some (small) excess noise was measured only when injecting the line at 58Hz, elsewhere it is an upper limit.
  • Figure 2: is the projection of HALL acoustic noise to Hrec using the colored noise. In this case excess noise in Hrec was produced between 40 and 80Hz.
  • Figure 3: is the projection of DET lab acoustic noise to Hrec using the colored noise. In this case the tentative indication is that environmental noise in DET lab acoustic noise is close to limit Hrec around 40-50Hz.
  • Figures 4 and 5 show the measured coherence between Hrec and the microphones (Hall and SQZ bench) during the injection of the 58Hz line and of the colored noise. In both cases there is an hint of coherence, but very little.

The lack of coherence means a non linear coupling path like scattered light. Therefore these projections have to be considered be only indicative.

The injection should be repeated in the DET lab to have a more reliable projection of DET microphones.

We also notice that the two projections (lines and colored noise do not agree much in the significant region 40 to 80Hz, it seems that the colored noise was much more effective than the lines in exciting Hrec, this might be because the narrow lines missed to excite the modes of the scattering component.

Images attached to this comment
verkindt - 23:54 Thursday 02 May 2019 (45804) Print this report
The following plots show some additional information about the effect of woofer acoustic noise injections on h(t):
Plot1: spectrograms of the acoustic noise injected (ENV_NOISE_CEB_DetTerrace) and its detection by microphones
in CEB (ENV_CEB_MIC) where only a component around 60 Hz is seen and on squeezing bench (ENV_SQZ_MIC) where
most of the components of the broadband noise injected are visible. Are shown also the spectrograms of hoft and hoft_clean
where only some intermittent noise around 50 Hz is visible.
- Plot2: shows a zoom of plot1 where we can clearly see that the result of the acoustic noise in h(t) is "modulated" in amplitude
with a periodicity of about 15 sec.
Plot 3: shows that, at about the time of the loudest acoustic noise injection, some coherence appears between h(t) and ENV_CEB_MIC
and between h(t) and ENV_SQZ_MIC

Also, I tried to run Silentec on h(t) during the loudest acoustic noise injection time period
in order to find some contribution of products of acoustic auxiliary channels in the h(t) signal between 30 Hz and 70 Hz.
The result below shows nothing very conclusive:

GPS aux. channels products contribution Q of the aux. channels product to h(t) between 30 and 70 Hz
1240309662.50 [1] V1:ENV_LB_MIC*V1:ENV_TCS_CO2_WI_MIC : Q=21.88% <<<<<<<<<<<<<<<<<<<
1240309671.50 [1] V1:ENV_NOISE_CEB_DetTerrace*V1:ENV_LB_MIC : Q=23.2104% <<<<<<<<<<<<<<<<<<<
1240309672.00 [1] V1:ENV_LB_MIC*V1:ENV_TCS_CO2_WI_MIC : Q=20.8125% <<<<<<<<<<<<<<<<<<<
1240309676.50 [1] V1:ENV_LL_ATRIUM_MIC*V1:ENV_LL_ATRIUM_MIC : Q=21.8277% <<<<<<<<<<<<<<<<<<<
1240309677.50 [1] V1:ENV_LL_ATRIUM_MIC*V1:ENV_LL_ATRIUM_MIC : Q=21.9007% <<<<<<<<<<<<<<<<<<<
1240309689.50 [1] V1:ENV_NOISE_CEB_DetTerrace*V1:ENV_NOISE_CEB_DetTerrace : Q=25.9784% <<<<<<<<<<<<<<<<<<<
1240309690.50 [1] V1:ENV_SQZ_MIC*V1:ENV_SQZ_MIC : Q=25.6153% <<<<<<<<<<<<<<<<<<<
1240309695.00 [1] V1:ENV_LB_MIC*V1:ENV_TCS_CO2_NI_MIC : Q=20.2872% <<<<<<<<<<<<<<<<<<<
1240309695.50 [1] V1:ENV_EIB_MIC*V1:ENV_EIB_MIC : Q=20.2872% <<<<<<<<<<<<<<<<<<<
1240309696.00 [1] V1:ENV_SQZ_MIC*V1:ENV_NOISE_CEB_DetTerrace : Q=20.2872% <<<<<<<<<<<<<<<<<<<
1240309701.00 [1] V1:ENV_EDB_MIC*V1:ENV_TCS_CO2_WI_MIC : Q=26.3575% <<<<<<<<<<<<<<<<<<<
1240309702.00 [1] V1:ENV_SQZ_MIC*V1:ENV_SQZ_MIC : Q=26.2144% <<<<<<<<<<<<<<<<<<<
1240309702.50 [1] V1:ENV_SQZ_MIC*V1:ENV_SQZ_MIC : Q=21.6918% <<<<<<<<<<<<<<<<<<<
1240309708.00 [1] V1:ENV_LB_MIC*V1:ENV_TCS_CO2_WI_MIC : Q=21.7782% <<<<<<<<<<<<<<<<<<<
1240309711.00 [1] V1:ENV_LB_MIC*V1:ENV_TCS_CO2_NI_MIC : Q=23.7171% <<<<<<<<<<<<<<<<<<<
1240309713.00 [1] V1:ENV_LB_MIC*V1:ENV_TCS_CO2_NI_MIC : Q=22.6683% <<<<<<<<<<<<<<<<<<<
1240309717.00 [1] V1:ENV_LB_MIC*V1:ENV_TCS_CO2_WI_MIC : Q=26.7048% <<<<<<<<<<<<<<<<<<<
1240309719.00 [1] V1:ENV_EDB_MIC*V1:ENV_LB_MIC : Q=26.1539% <<<<<<<<<<<<<<<<<<<
1240309722.00 [1] V1:ENV_LB_MIC*V1:ENV_TCS_CO2_WI_MIC : Q=28.0408% <<<<<<<<<<<<<<<<<<<
1240309722.00 [2] V1:ENV_EIB_MIC*V1:ENV_TCS_CO2_NI_MIC : Q=20.3903% <<<<<<<<<<<<<<<<<<<
1240309722.50 [1] V1:ENV_SQZ_MIC*V1:ENV_SQZ_MIC : Q=29.9392% <<<<<<<<<<<<<<<<<<<
1240309723.00 [1] V1:ENV_LB_MIC*V1:ENV_TCS_CO2_NI_MIC : Q=25.9539% <<<<<<<<<<<<<<<<<<<
1240309724.00 [1] V1:ENV_SQZ_MIC*V1:ENV_SQZ_MIC : Q=20.0296% <<<<<<<<<<<<<<<<<<<
1240309725.00 [1] V1:ENV_NOISE_CEB_DetTerrace*V1:ENV_EIB_MIC : Q=37.6784% <<<<<<<<<<<<<<<<<<<
1240309725.50 [1] V1:ENV_EIB_MIC*V1:ENV_EIB_MIC : Q=39.3615% <<<<<<<<<<<<<<<<<<<
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