DRAFT REPORT - shift in progress; the report will be finalized and convalidated at the end of the shift
ITF found in Science mode.
At 15:32 UTC ITF in Commissioning mode for the planned activity.
Due to an urgent patch on NetApp Storage array that host all online OS Disk some olservers needed a reboot.
Here the list:
- olserver222
- olserver225
- olserver411
- olserver412
- olserver423
- olserver424
I have analyzed the SSFS injections done on Sunday (#65112) and on Monday. I have attached the projection of the SSFS error signal and the sensing noise as witnessed by the quadrature. They haven't changed significantly from the last ones (#65042).
ITF found in LOW_NOISE_3_SQZ and in Science Mode.
06:16 UTC - S240919bn
From 08:13 to 08:19 UTC, two drops in the BNS range below 40 Mpc (TBC), pict1. I exit from Science Mode for one minute.
ITF stable locked for the whole shift.
- guard tours (UTC):
21:16 --> 21:44
23:06 --> 23:36
1:06 --> 1:37
3:11 --> 3:41
ITF found in LOW_NOISE_3_SQZ and in Science Mode. It unlocked at 18:09 UTC, it was possible to relock at the first attempt. ITF back in Science Mode from 18:56 UTC.
ITF left locked.
Guard Tours (UTC)
17:06 - 17:36
19:04 - 19:32
ITF in Science mode for all the shift.
- guard tours (UTC):
21:00 --> 21:34
23:00 --> 23:29
1:00 --> 1:32
3:00 --> 3:28
ITF found in LOW_NOISE_3_SQZ and in Science Mode, it unlocked at 13:03 UTC due to the strong wind.
It was possible to relock the ITF twice, once at 16:06 UTC with unlock at 16:12 UTC, and the second one from 17:17 UTC to 17:37 UTC, both possibly caused by the weather conditions. Due to the instability of the ITF it was not possible to perform the planned ENV activity.
ITF back in LOW_NOISE_3_SQZ and Science Mode from 18:27 UTC, still locked.
Guard Tours (UTC):
17:00 - 17:28
19:30 - 19:56
ITF found in Science mode.
At 6:00 UTC ITF in Maintenance, below the list of the known activities:
- periodic tasks performed by the operator:
- TCS Chiller Refill
- OMC scan in single bounce
- Thermal Camera Reference
- TCS Power Checks
- Check of IMC Working Point and Position
- cleaning of the experimetal areas;
- NEB LPG boiler maintenance;
- Compressors maintenance;
All the activities concluded at around 10:00 UTC; at that point I started to relock the ITF.
It unlocked at the first attempt in ACQUIRE_LOW_NOISE_3; then the wind increased a lot making impossible to lock the ITF. For this reason at 11:12 UTC I set Bad_weather mode.
At 12:59 UTC ITF in Science mode.
Here is the noise budget computed after the noise injections on September 16th.
The coherence with hrec is rather poor, but the contribution of SRCL, MICH and PRCL on hrec seems larger than it was on September 9th.
On DARM, the effects of CARM slow are still considerable.
The highlighted period of excess noise and glitches appears to be concomitant with an earthquake recorded by the Guralp seismometer of the three corner buildings, North (blue), West (orange) and Central (green).
Figure 1: signals of the seismometers in the three buildings in the west direction in the hours around the period identified in the first post.
In the same time interval also monitors such as V1:ENV_SEISMON_N_WARNINGS, V1:ENV_SEISMON_MAG_1, V1:ENV_SEISMON_GPS_LATEST_1 and V1:ENV_SEISMON_GPS_EARLIEST_1 were active.
/data/archive/rawdata
and
/data/archive_raw
will be unavailable for some minutes.
During this morning maintenance (from 6:55 to 7:09 UTC) the processes involved in the Virgo low latency distribution which were moved to olserver55 last week have been put back to olserver54.
No DMS alerts in the last 8 hours.
- guard tours (UTC):
21:23 --> 21:51
23:00 --> 23:27
1:00 --> 1:27
3:00 --> 3:26
ITF found in LOW_NOISE_3_SQZ and in Science Mode.
15:30 UTC - CALIBRATION mode set.
15:34 - 15:53 UTC, after the BNS range glitch, inject_lsc.py. OK! without unlock.
At 15:55 UTC I manually unlocked ITF and started the planned calibrations:
15:56 UTC - CALIBRATED_DELAY
16:09 UTC - CALIBRATED_SRNI. Upon concluded I had to realign the cavities (WE +2urad ty)
From 16:30 to 16:42 UTC, M. Cifaldi checked the TCS powers.
16:42 UTC - CALIBRATED_DF_INtoEND_LN.
ITF back in LN3_SQZ at 18:10 UTC. SCIENCE MODE set.
18:44 UTC - S240916ar
Guard tour (UTC):
17:10 - 17:37
19:08 - 19:36
According to CR, at 16.03 UTC WI INNER DAS has been switched OFF.
The current power values are reported in the table below.
| | | CH [W] | DAS IN [W] | DAS OUT [W] |
| WI | On the pickoff | 0.284 | 0 | 0.260 |
| On the ITF | 0.046 | 0 | 1.596 | |
| NI | On the Pickoff | 0.635 | 0.055 | 0.613 |
| On the ITF | 0.104 | 0.340 | 3.68 |
At 16.30 UTC I also performed a power check for t
Observing that the glitches reported in the previous post have the arc-like shape typical of Scattered Light, I used the usual code for studying this noise and it was quite easy to find the location of the scatterer that generates these arcs. By correlating all channels with position units, from which their instantaneous velocity was derived, it turned out that a large number of channels related to the Suspended North End Bench had a correlation larger than 80% with the arc frequency in Hrec. In the attached text file, I report the list of those with Pearson coefficient greater than 0.3.
Figure 1: spectrogram of Hrec during the period of excess noise with superimposed the arc frequency obtained from the most correlated channel, SBE_SNEB_SA_F0_diff_LVDT_z_500Hz, with Pearson coefficient of 0.83.
I report here the preliminary observation of excess noise at the beginning of the last segment in scene mode, 12:29 - 12:48 UTC on September 16. This is visible in range oscillations of more than 10 Mpc. The analysis of the causes is still ongoing.
Figure 1: BNS range time series exhibiting large oscillations in the ~20 minutes right after the science mode is being engaged.
Figure 2: spectrogram of Hrec during the same data interval as the previous figure, showing a sequence of loud glitches at low frequency.
Observing that the glitches reported in the previous post have the arc-like shape typical of Scattered Light, I used the usual code for studying this noise and it was quite easy to find the location of the scatterer that generates these arcs. By correlating all channels with position units, from which their instantaneous velocity was derived, it turned out that a large number of channels related to the Suspended North End Bench had a correlation larger than 80% with the arc frequency in Hrec. In the attached text file, I report the list of those with Pearson coefficient greater than 0.3.
Figure 1: spectrogram of Hrec during the period of excess noise with superimposed the arc frequency obtained from the most correlated channel, SBE_SNEB_SA_F0_diff_LVDT_z_500Hz, with Pearson coefficient of 0.83.
The highlighted period of excess noise and glitches appears to be concomitant with an earthquake recorded by the Guralp seismometer of the three corner buildings, North (blue), West (orange) and Central (green).
Figure 1: signals of the seismometers in the three buildings in the west direction in the hours around the period identified in the first post.
In the same time interval also monitors such as V1:ENV_SEISMON_N_WARNINGS, V1:ENV_SEISMON_MAG_1, V1:ENV_SEISMON_GPS_LATEST_1 and V1:ENV_SEISMON_GPS_EARLIEST_1 were active.
ITF found in SCIENCE mode (LOW_NOISE_3_SQZ).
At 06:08, I briefly set the ADJUSTING mode as Cifaldi performed the planned intervention on WI inner DAS (see #65157).
After shortly returning to SCIENCE mode, the ITF unlocked at 06:10 UTC.
After multiple attempts, the ITF returned to SCIENCE mode at 10:28 UTC.
At 11:44 UTC, I manually unlocked the ITF as planned for testing the lock acquisition. The ITF successfully locked at 12:27 UTC.
According to commissioning plans, this morning, at 06.08 UTC, WI INNER DAS has been switched on with the ITF in adjusting.
The new CO2 power values are reported in the table below:
| | | CH [W] | DAS IN [W] | DAS OUT [W] |
| WI | On the pickoff | 0.284 | 0.019 | 0.260 |
| On the ITF | 0.046 | 0.115 | 1.596 | |
| NI | On the Pickoff | 0.635 | 0.055 | 0.613 |
| On the ITF | 0.104 | 0.340 | 3.68 |
ITF found in SCIENCE.
- 23:02 UTC: The ITF was unlocked due to an earthquake (Mwp 6.4, Canada).
- 23:04 UTC: I set the EARTHQUAKE mode in the ITF status. The ITF was placed in LOCKED_ARMS_IR to prevent multiple unlocks and to wait for the effects of the earthquake on the suspensions to subside.
- 00:51 UTC: The ITF returned to SCIENCE mode.
- 01:04 UTC: The ITF was unlocked.
- 01:59 UTC: The ITF returned to SCIENCE mode.
- 02:10 UTC: SQZ was disengaged, and the ITF transitioned to LOW_NOISE_3 and out of SCIENCE due to an unexpected drop in the Hrec BNS range (see attacched picture).
- 02:12 UTC: SQZ was re-engaged, and the ITF returned to LOW_NOISE_3_SQZ and SCIENCE mode.
ITF left in SCIENCE.
Guard Tour (UTC)
21:00 - 21:31
23:03 - 23:39
01:00 - 01:33
03:00 - 03:35
I continue here the analysis of the loud (SNR > 100) glitches identified in the first post. Most of them appear to belong to the same family, characterized by a burst of energy of a few tenths of a second, with a peak frequency (the one typically reported in glitchgrams) between 10 and 30 Hz, and a broadband structure in which some resonances stand out, such as 74, 150, 500 Hz: Figure 1. Typically, these are frequencies where bilinear couplings are strongest and are excited in bad weather conditions. Compare, for example, the MONET results for September 12 (bad weather) and September 14 (calm) around the 74.4 Hz calibration line. At this link, you can find the omicron scans of some glitches belonging to this family.
In the hour of data shown in Figure 2 of the first post, there are also two glitches belonging to the 25-minute family, respectively at GPS 1410153390.86 (05:16:12.86 UTC) and 1410155120.89 (05:45:02.89 UTC), with a waveform clearly distinguishable from that of the other family: Figure 2.
I investigated Michal's hypothesis (confirmed by Didier during the DetChar meeting on Friday) about the coherence of LSC_MICH and LSC_SRCL during the period shown in figure 4 of the first post. Figure 3 and 4 show the coherence spectrograms between Hrec and LSC_MICH and LSC_SRCL respectively. As hypothesized, there is a band between 10 and 30 Hz in MICH with increased coherence between 5:16 and 5:20 UTC, and possibly again between 5:44 and 5:48 UTC. In SRCL instead a line is noted at about 19 Hz.
Finally, I add to the characterization of this period of bad weather the glitchgram and time series of the seismometers between September 12 and 13: Figure 5.
No DMS alerts in the last 8 hours.
- guard tours (UTC):
13:45 --> 14:15
15:45 --> 16:15
17:05 --> 17:31
19:30 --> 19:59
ITF found in SCIENCE mode (LOW_NOISE_3_SQZ). It remained locked for the whole shift.
No DMS alert in the last 8 hours.
Guard tours (UTC):
- 05:55 - 06:40
- 07:50 - 08:25
- 09:45 - 10:15
- 11:50 - 12:20
