This afternoon we performed some measurements to verify the mismatch towards the arms. The last measurement done is reported in #63374.

First, we performed the free swinging method, giving a kick on the end mirrors (with the dampers opened). The GPS of the kick (we gave the kick simultaneously for the West and North arms) is 14:17:00 UTC.

However, when analysing the data we could not find reasonable values of mismatch. We need to verify if there is any problem with the Matlab code to debug, or there was something wrong with the measurements. In Fig. 1 we can see the time window of the free swinging mirrors. To be noted that the west arm starts swinging after roughly 15 seconds with respect to the North Arm. On Fig.2 we can see the surposed flashs of B7 and B8.

Then, we perform the measurements with the Green Scan. The GPS in this case 14:30:43 UTC (Fig 3). Figs 4 and 5 show the scans of the TEM 00 mode and TEM 02 mode respectively. In this case, for the north arm we found 3.3% and 1.4% for the west arm, as shown in Fig. 6.

DRAFT  - REPORT  IN PROGRESS - will be finalized at the end of the shift

Upon reaching the site, I've found the ITF in LOW_NOISE_3_SQZ and Science Mode.
At 14:00 UTC I set the ITF in Commissioning Mode to allow the planned activity for the afternoon (Characterization for EM RH tuning) carried out by Nardecchia, de Rossi, Melo, Gouaty.
At 14:17 UTC the ITF was manually unlocked by De Rossi and Melo with a "kick" of the NE and WE Suspensions.
At 16:06 UTC we reached again CARM_NULL_1F, and waited one hour before performing the OMC Scan.
Scan started at 16:08 UTC, scan in progress.

In order to try to mitigate this problem, we have increased the shutter pulse duration from 20 ms to 40 ms for both B1_PD1 and B1_PD2. The SDB2_dbox_bench process has been reloaded at 14h52m27-UTC.

Upon arrival, I found the ITF locked and in SCIENCE mode.

At 6:05 UTC I set the MAINTENANCE mode. Here is the list of the activities communicated to the Control Room:

- Cleaning of the Central Building and the DET Lab (external firm managed by Menzione);

- TCS chiller refill (Menzione);

- Replacement of the electric post-heating coil for the AHU 1_SX of the Mode Cleaner (external firm managed by Soldani);

- Checks on the HVAC plants (Soldani);

- ELE_QGBT process update (Ballardin);

- ENV_MCB_MAG_N magnetometer substitution, see #64189 (Paoletti)

During the shift, I performed these periodic tasks:

- At 6:10 UTC I set the SINGLE_BOUNCE_NI state. OMC locked from 6:30 UTC to 6:35 UTC. OMC scan performed from 6:45 UTC to 7:06 UTC;

- Check of IMC working point and position from 7:20 UTC to 7:30 UTC;

- Acquisition of TCS thermal camera references at 7:47 UTC;

- At 9:00 UTC checks on TCS powers (see table below for results);

At 9:03 UTC the SNEB horizontal position control loop opened. I closed it at 9:28 UTC.

NCAL flag on DMS became red at 8:20 UTC. Experts informed.

As requested by Degallaix, I performed a slow FSR scan with the green laser from 10:44 UTC to 11:13 UTC. After that I set the PREPARE_SCIENCE mode.

During the lock acquisition a CITF alignment was required. The SUS_PR and DRMI_LOCK Metatron nodes got stalled, requiring a restart of the latter.

I left the ITF in LOW_NOISE_3_SQZ state and SCIENCE mode at 13:10 UTC.

This morning between 8:00 and 10:25 UTC I slightly changed the position of the central crop in B1p camera image, in order to better catch the central spot. See previous crop in first attachment (in LN3), current one in second attachment (in arms locked)

VPM process has been reloaded and, after a fix, the 2 new flags are correctly display. I'll watch the new flags regularly in the following days to check that the parameters are correct.

Following the CO2 power scan done by the operator (see entry 64186), I just slightly tuned the CH powers to restore default. The action concluded at 10.03 UTC.

Today also FIAMM01 (Carabinieri) had some flyover near CEB (08:40 UTC)

The estimated distance is ~ 200m, the height was ~ 200m (credits: flightradar24), well inside the NOTAM area.

The signal is very clearly visible in the CEB microphones. The ITF was unlocked (maintenance).

The weather station did not transmit during a long time (to be quantified). I disconnected it and checked the serial-to-Ethernet on bench with an universal power supply, since it is very difficult extracting its own jack from the box on the wall. No response, and FPGA very hot. No spares of the same kind presently available, only one Netcom Plus 211 with a different supply connection.

I leave the Meteo station disconnected and the box opened, as long as we find a solution.

The process ELE_QGBT interrogates different electrical nodes; when a node does not respond the process automatically goes into the Error state. Obviously, data related to that node is not sent to the DAQ. When the problem disappears, the process automatically goes in the Golden state (so it not necessary to restart the process from VPM) and the slow monitor date is sent again to DAQ.

Today at 10h24 LT I put in operation a new version (v6r9) of this server to try to detect nodes generating problems. In this new version when a node does not respond, the ELE_QGBT goes in Active State and not in Error State.

Figure 1, the 157Hz bump decrease in the first hour of each lock, Figure 2 during the shift yesterday it did not decrease because the MICH SET loop was intentionally disable for an hour, and then MICH SET adjusted quickly by hand. 

Figure 3 confirms that RIN coupling due to a MICH offset is the dominant coupling path fo the 157Hz bump. Blue was with a large RIN coupling to DARM, red  and yellow are with the coupling intentionally increased by adding a MICH offset in the wrong direction, and green purple and green are with the MICH offset adjusted to minimize the RIN coupling (at 1.5kHz).

Figure 4. As seen benfore when the PRCL offset is adjusted to minimize the frequency to amplitude conversion on B2 (blue and red lines), the B2 Audio spectrum is much cleaner, especially at high frequency.

Figure 5 and 6 what is surprising is that looking at the B2 quadrants. In the vertical direction the coupling of frequency noise (227Hz line) decrease in the vertical direction by a factor few, but in the horizontal direction there is no significant change. Does that mean that the coupling has a significant contribution of HOM? Note that this is true only for B2 QD1, on B2 QD2 the line at 227Hz is not visible in neither the H nor V direction, at any of the times. And on both quadrant the sum channel sees the line clearly and decreases by a factor 10 when adjusting the PRCL offset.

/users/mwas/ISC/RINanalysis_20240506/analyseRIN.m

The probe has been removed today from the MC tube, during the maintenance.

The ENV_MCB_MAG_N magnetometer was defective as of October 2, 2023 at 00:03:05 UTC.

Today we changed it with a new one (MFS-06e). We also had to use a different type of cable (the new magnetometer uses a different connector), via an adapter.

The signals seem to have returned to normal values.

This morning, the threshold on SDB1_slow_shutter_OMC1_T1_fast_RMS used to monitor the closing of the slow shutter has been adjusted to 6e-9. DetMoni restarted at 07h19m23 utc.

ITF in Science mode for all the shift.

Guard tours (time in UTC)

From 21:00 to 21:30; from 23:00 to 23:30; from 1:30 to 2:00; from 3:30 to 4:00

In this afternoon shift science mode stopped from 15:35UTC to 18:30UTC for daily calibration and commissioning (RIN coupling vs MICH and PRCL offsets), the ITF unlocked at 15:58UTC with a DOWN command from my ITF_LOCK client, I missclicked on the metatron client instead to set DOWN the CALI node I did it for ITF_LOCK without realizing it; the relock was a bit longer with three fails two locking at CARM_NULL_1F and one meanwhile locking the OMC (#64183).

-guard tours(UTC):
17:11 --> 17:39
19:03 --> 19:30

Air Conditioning
from 14:50UTC the MC building air conditioning started to malfunction with a little increasing of the hall temperature (see plot); experts aware of the problem, an extraordinary maintenance of the system is foreseen for tomorrow.

Calibration
- 15:36UTC: CALIBRATING_DF_DAILY;

Shift started with a couple of unlocks.

17:56 UTC turned off MICH SET loop (putting MICH_SET_CAL to zero)

MICH set loop had not converged, so PSTAB was not yet at zero.

18:00 UTC (5min) PRCL set = 8.0 to zero the frequency to amplitude conversion on B2.

18:06 UTC (5min) PRCL set = 8.0, MICH set = -5.0, to increase PSTAB to DARM coupling

18:13 UTC (5min) PRCL set = 0.0, MICH set = -5.0

18:23 UTC (5min) PRCL set = 0.0, MICH set = 12.0 to zero the PSTAB to DARM coupling

18:29 putting back MICH SET loop (cali at -100000)

Figure 1. I have noticed any changes in the sensitivity during this test, appart from the 157Hz bump getting smaller when changing the MICH set to zero the PSTAB to DARM coupling. To be checked more carrefully if MICH set is really the cause.

Figure 2. Summarizes the change in PRCL and MICH offset. A PRCL offset of 8 changes the PSTAB to DARM coupling by about the same amount as a change of MICH offset of 5.

https://git.ligo.org/virgo/commissioning/commissioning-tasks/-/issues/52

Today during the lock acquisition I have noticed that there was power on B1 PD1 while trying to lock the OMC.

Figure 1 shows fluctuation on B1 PD1 even though the voltage bias is off.

Pressing the close button of the shutter in vpm worked to close it, but before that I panicked and closed B1 PD3  and turned off its voltage bias instead. Which caused an unlock first as DET_MAIN has seen the B1 PD3 being turned off and put the interferometer in DOWN.

Maybe the B1 PD shutters are starting to be stuck again because the interferometer locks are becoming too long, and they are not open/closed often enough. We may need to add checks in the automation to check they are indeed closed.

The DCP measurement is likely just a witness of something else changing.

Figure 1 shows the same as on Paolo's figure, the optical gain changes from 3e9 to 2.9e9 and the DCP frequency changes by ~5Hz.

Figure 2 shows the squeezing test of last week. The SR TY set point was changed intentionally by ~25Hz, and the optical gain changed from 3e9 to 2.85e9.

So the change in DCP that occured during the weekend could explain only ~30% of the change in optical gain.

From the recent long lock, one can notice that two small drops of the range happen together with drops of the optical gain. At the same time, the double cavity pole measured by Hrec increases a bit, while the one measured by ACL is kept constant by SR_TY loop. A possible guess is that the error signal of SR_TY loop is sometimes slightly corrupted by something which does not affect the DCP computation done by Hrec. The effect would be eventually a little change of SR_TY working point and a consequent increase of the actual DCP, together with an increase of mystery noise. But we should also consider the possibility that the optical gain is changing because of something else and the measurement of DCP is just a witness of that. We should check if a change of DCP by 4 Hz can explain the visible drop of optical gain, or usually a larger DCP variation is required.

I would also add that maybe we could acquire some day of data at a lower DCP setting, in order to check if the current setting is still the one which maximizes the range.

Today at 13:00 LT we could see an airplane flying over the main building, probably just departed from the lane nearby; one minute later it can be spotted in the CEB microphone signals, but it did not have an impact on Hrec; some 25 minutes later it probably came back along the same route, luckily causing no effect again on the sensitivity.

ITF found in LOW_NOISE_3_SQZ and in Science Mode. It kept the lock for the whole shift.

DAQ
From around 10:39 UTC the process ELE_QGBT was reported as not responding on VPM (Orange State) and as not working on DMS (red flag). At 10:46 UTC I restarted the process via VPM to restore the nominal condition.